Betting Guides

At OnlineBetting we provide more than just offers and reviews and we aim to give you as the punter a comprehensive resource for all your betting needs. In this section you will find all you need to know about betting. From what types of bets are available and what they mean to guides on common offers and event, it's all in here.

Best Betting Sites Guide

betting sites 2Our guide to the UK's best betting sites is designed to let you, the punter, find the online bookmaker(s) that fits best with you. We have dissected all the major features from the top bookies with a UK gambling commission licence. Read about the markets they cover and in what depth, what their top betting offers are, interfaces, mobile betting, live betting, streaming availability, payout limits, odds, history, customer service, payment methods and more. For whatever reason you like to bet make sure you bet with your perfect betting sites.

Sports Betting Guide

sports betting guideSee our sports betting index and find everything you need to know to bet on your favourite sports whether you are a seasoned professional or a complete amateur. We have guides on what bets are available by sport and how to place them. We show you where to find the best live betting and streaming, what top competitions and tournaments to look out for as well as the best bookmakers for betting by sport. Find out where sports originated in our sports history guides, where to get the best odds and payouts and other articles on types, terminology and more to help you get the most from your sports betting.

Payment Methods & Banking Guide

Payment homeThe beauty of online bookmaking is it has changed the way people fund their betting wallets, you can now use eWallets such as PayPal and Skrill as well as cash voucher systems such as PaySafeCard, and did you know you are still able to deposit and withdraw from betting sites using cash in store? In our banking articles you will find all the minimum and maximum deposit and withdrawal limits including information on fees and sign up bonus availability. Also find information on how to set up and use various payment methods.

Low Stakes and Low Deposit Betting Sites

low depositIn the old days when we all used to bet in bookmakers shops the idea of minimums didn't really apply, you could place a bet with a twenty pence piece or a twenty pound note and nobody cared.  Online betting accounts however need funding and this means minimums.  Most are set at £10 but this can be often higher, and what if you don't want to put £10 in, what are your options, see all of our lowest stake bookmakers.

High Stakes and High Pay Out Bookmakers

Cash imageThe choice of online bookmakers has never been bigger, there are hundreds to choose from and even though we only cover the most reputable bookies on here there are still over 15 of them. Smaller and newer betting sites can often have much lower pay out limits, especially for smaller sports, so if you like to bet big or on long odds it's worth finding an online bookmaker with high stake and payout limits.

Maximum Payout and Stake Limits

payout capAll sports betting sites have payout limits and it is useful to be aware of these.  You don't need to be a big bettor to fall foul of a payout maximum, this could happen with small stakes on bets such as accumulators with big odds.  Payouts often vary by sport, meaning that just because it is say £1M for football doesn't mean it will be for darts, for example. Limits also vary by markets so some lines pay less than others.  In our guide we list payment maximums by sport for all the sites we list.

Shop Card Schemes To Deposit, Bet & Withdraw

coral connect cardIt is now entirely possible to link your online account to cards that can be used at some of the biggest UK bookies with a high street presence to allow you to deposit, bet and withdraw from one account.  This means you can retain online offers and benefits, often get additional offers, deposit or withdraw as little as £1 in cash instantly and with some you can now even track your bets placed in store, cash them out and even more.  These cards can add a lot of value to regular bettors.

How To Bet Guide: From Beginners to Professionals

how to bet guideIf you have never placed a bet in your life or you bet every week our guide will have something for you. Whether you want to find out the very basics of how to place a wager, want to try out some new types of bets or you are just making sure you are getting the most from your wagers then take a look at our in depth guide. By following a few simple steps you can not only expand your betting portfolio but get the best possible value at the same time in our how to bet guide.

Football Articles

football guidesFor such a simple and beautiful game there is a lot to be said quite literally about football. As the biggest spectator sport on the planet and representing around 70% of wagers in the UK there is a lot to understand when it comes to betting on football. In our football guides section we discuss everything from the history of football, the best bookies, guides on bet types such both teams to score, accumulators and more.

Horse Racing Articles

horse racingHorse Racing has a long history and as the original betting sport it has accumulated many rules and terms that can seem daunting to the uninitiated. Are you are puzzled as to what Rule 4 means, what happens in a dead heat or want to know the difference between grades and classes? Don't worry we have clear and easy to understand guides and articles to help you get the most value from your racing bets.

Bet Types

betting guide home imageDo you want to know what is a Lucky 15 or how to place an each-way bet? See our guide to Bet Types with real examples of how these bets work in practice and what your risks and rewards are when betting in different ways.

From single bets to spread bets you can pretty much do it online these days. Want to place a multiple bet, well there are more options than just your run of the mill accumulator. How about having a go at a forecast or a conditional bet? Ever wondered what a Union Jack bet is or a Roundabout.

Live Streaming Sites and How to Stream

live streamThere is no need to pop down the bookmakers shop anymore to watch a game or a horse race as many now provide live streaming services online. Collectively there are hundreds of thousands of live events broadcast each year. Some sites are certainly better than others for both coverage and the quality of the stream. In our live streaming guide find the best streaming sites, details on how to stream and what events you are likely to find. We also talk about integrated and non-integrated systems as well as streaming strategies and rules.

Live In Play Betting Sites and How To Bet Live

bet liveLive betting is now offered as standard by pretty much every online betting site.  More bets are now placed in play than pre-event which tells you how popular the feature has become in the space of a decade or so. Of course just because all sites offer the ability to bet live doesn't mean they are all equal, with some operators far better than others when it comes to in play odds and features.  Find out who our recommended live betting sites are and why along with a guide to get the most out of betting in play alongside other features such as cash out.

Cash Out and Partial Cash Out Guide

Cash imageMost online betting sites now provide Cash Out for major sports markets and some now provide partial cash out allowing you to cash in some of your wager leaving the rest to run. In our guide find the bookmakers with the best cash out features, find out how odds are generated, if the odds are fair, market availability, how to maximise profits and reduce losses and how to use cash out in conjunction with promotions.

Best Betting Apps & History Of Gambling Apps

betting on sports app at homeIn the early days many people believed apps would never be used much for things like betting and gaming, they couldn't have been more wrong.  Mobile betting now represents around 70% of all gambling and around three quarters of people who bet on mobile use apps.  Apps are more personalisable compared to websites as well as being faster and more accessible coupled with the ability to use them on multiple devices.  Of course there are drawback too, read our guide for more.

VIP Programs For Sports Betting

VIPIf you bet more than £100+ a month you would likely qualify for a VIP program with some bookies.  VIP schemes are not as common for sportsbooks compared to casinos but there are still many good options out there, and if you do bet fairly big then why not take the benefits that come with them.  These can include higher free bets and bonuses, better prices and sometimes even high level hospitality.  There are pitfalls too to be aware of such as minimum bet limits that could lead to problem gambling.

Bet Editing Guide

edit bet thumbSome leading Online Bookmakers are now providing tools that allow you to edit bets both pre-event and live in play. In our bet editing guide you can read about betting sites that offer various bet editing features and how they work.  Live bet editing is basically a form of cash out but instead of taking the winnings you immediately place a second, edited, bet.  Used sensibly bet edit tools can not only be fun they can mitigate loses and boost winnings.

How To Request Your Own Bets

request a betYou have always had the option to contact a bookmaker and ask if they will give you a price for an event or outcome.  The problem is this could take days sometimes meaning you needed to pick your wagers well in advance.  Modern betting tools combined with mobile apps and social media platforms such as Twitter mean you can now request bets for virtually anything in an instant.  In our guide we discuss the value of these features, which are the best ones to use, and how to get the best out of them.

Bet Builders and Building Your Own Bets

buildingFor top level football some betting sites now offer bet builders.  Like request a bet features these let you combine related markets form an individual match into a larger multiple bet that better reflect your predictions of what will happen.  These features are great for giving you more control and provide a way to increase the odds for small stakes bets, they are also much quicker than traditional bet requests and allow you to compare more markets in parallel.

Biggest Bookies and the UK Gambling Industry

number crunchingThe UK has one of the biggest regulated gambling markets in the world and through a long history of Brits liking a bet it has created some of the worlds biggest multi-billion pound betting companies.  In our article we look at the UK's largest betting operators and how they became so big along with the UK gambling market as a whole.  From the distribution of gambling revenues online and offline to the evolution of betting in the UK we dissect the UK betting market.

Mergers & Acquisitions In The Betting Industry

mergers and aquisitionsThe betting game is one of the most competitive there is, online especially, many would even say the gambling industry is more about raw capitalism than anything outside of banking. Still in spite of the high competition and huge revenues on offer many of the biggest operators continue to acquire other brands or merge to create larger and larger companies.  But what does this mean for the future of the betting industry?

White Label Bookmakers and Sportsbook Platforms

platform providersIf you have ever looked at a betting website or app and thought it looks and feels surprisingly similar to another, that is probably because they run on the same platform.  One of the easiest ways for a new betting site to set up these days is to use a platform provider to actually deliver all the nuts and bolts, markets, banking, ID checking, support, odds, etc., with the brand basically just picking what features they want and providing their own logos and colours. Find out who are the biggest white label and platform providers.

BetVictor Bet Calculator

bet typesThere are a lot of bet calculators around for working out returns from various wagers but almost no online bookmakers themselves have the feature.  Perhaps they don't want you to work out better value bets?  BetVictor however have a fantastic bet calculator, it allows you to work out the payouts form pretty much any bet type you could want to place, including forecasts and reverse forecasts.  Completely free to use, you don't even need an account. This is one of the most considered and user-focused features from what is already a very professional betting site.

Betting Glossary

GlossaryConfused what a Pony is or simply want to know where the name came from? What is a banker bet compared to a normal bet, how about a Patent or a Trixie, here we describe all those weird and wonderful terms you are likely to encounter in the world of online betting. We have created a comprehensive betting glossary for your reference.

History of Bookmaking & Gambling

bet slip 2It is likely that early humans were having a bet well before we even invented money.  Gambling for most of its history has however either been largely unregulated or generally illegal. In our guide to the history of bookmaking we track the evolution of betting in Britain through the ages including how law has changed and gambling habits have changed.  We also look at the very first bookmakers, betting sites and exchanges as well as the rise and fall of institutions such as the Tote and greyhound racing.  Finally we consider the furture of the gambling online.

Guide To Gambling Licences & law In The UK

licencingThe UK can now boast one of the best regulated yet most open and fair betting industries in the entire world. Every UK bookmaker and gambling operator must now possess a gambling licence issued by the gambling commission and this ensures customers can bet in a fair and honest way. Read out guide to find out about the current law, what the gambling commission is and what they do, what is required to get a gambling licence and a full list of bookmakers' licenses. Also read about the history of betting law and what to do if you have a complaint.

Betting & Gambling Tax in the UK

Gambling TaxRead our gambling and betting tax article to find out under what conditions you are require to pay tax when betting in the UK. We discuss both the old and current gambling tax law giving you information on the most up to date legislation.  We also tell you what to do if your a professional gambler and how to declare winnings.  Find out what happens if you spread bet and how this is taxed, get information on giving away your winnings, betting in another country, the history of betting tax and more.

Gambling Age Restrictions In The UK

Responsible Gamling 18Most of us know you have to be 18 years or older to gamble in the UK, well in actual fact it isn't quite as clear cut as that.  Depending on what form of gambling you participate in the legal age might be 16 (for lottery games, for example) or there may be no age limit at all (arcade and certain other games).  Should the age be set at 18 or is this just an arbitrary number plucked out of the air?  Read our gambling age article to discover what the current age laws are and what would be the effect on problem gambling if the age was increased using studies from other countries.

The UK Gambling Commission

gambling act 2005If you've read some of the guides on this site you will know how important it is to only bet with UK licenced brands when in the UK.  These licenses are issued and enforced by the UK Gambling Commission, but what exactly is the GC, where did it originate from and why do we need it?  What roles do they perform in regulating betting and gaming for British customers and how to do they ensure the law is followed?  In our GC article we tell you everything you need to know about the independent body and we also tell you what they don't do too.

Betting and Gaming Council

betting and gaming councilThe betting and gaming council is the body introduced in 2019 to oversee all forms of gambling in the UK.  The BGC replaces three previous bodies, the Remote Gambling Association, that used to oversee online betting, the Association of British Bookmakers, that used to oversee high street bookmakers and the National Casino Forum.  The idea is having one body will allow a consistent approach to gambling regulation across all platforms and the hope is this should enhance responsible gambling measures.

Problem Gambling and Fraud Prevention Measures

gambling protectionsProblem gambling and fraud prevention are hot topics right now when it comes to online gambling and many think the industry does not do enough to prevent it. Looking at other industries such as the financial sector there are tools available through software and monitoring that could go a long way towards protecting people further, so why are these not implemented widely by gambling companies? A large part of the problem is firms are largely allowed to self-regulate and so do we need independent systems in place?

Betting Systems Explained

betting systemsBetting systems have been around, well, as long as betting has been around. There are a lot of different systems from famous names such a Martingale, Labouchere, D'Alembert, right down to the dodgy system thought up by your mate down the pub. Whatever the system there is always a catch and rarely is there a way to ensure a win.  Even if there is the operators will catch you and stop you before long anyway. In our article we discuss all forms of sport betting and casino betting systems including how they work, if they work and where they originate. We tell you if the systems are legal, if you can be banned for using them and more.

Betting Odds Explained

betting oddsModern online betting is bow a global affair and this means you will now see odds and prices listed in several formats including traditional fractions more European decimals and even American moneyline formats. Some more continental bookies may only provide prices in decimal format and this is also common in exchange and index spread betting. There is really nothing to worry about. In our article you will explain betting odds including how to bet with different odds formats with conversion and comparison tables and real examples.

How Do Bookmakers Set Odds and Make Money

setting oddsBookmakers do not gamble when it comes to setting prices. Odds are set based on probabilities, in response to betting patterns and to balance the book. By understanding how bookmakers set odds you can spot the best value prices to add maximum value to your wagers. In this article we discuss aslo disucss how to calculate odds, how bookies balance books to ensure they always make money and how to spot high and low margin bets.

Beat The odds & Make Your Own Luck

beat the oddsThere is no guaranteed way to win when gambling but there are ways to ensure that when you do win you get the best possible value from your wager. Odds are set by traders and in general they undersell the likelihood of an outcome, hence how the bookie makes a profit. Traders are however human after all and although rare they do make mistakes and omissions. In this guide we discuss ways to spot overpriced odds lines on a regular basis as well as other strategies to beat the odds.

Guide To Responsible Gambling

Responsible GamblingGambling is fun but can also be addictive. In the UK we have some of the most stringent gambling regulation in the world and bookmakers are required by law to promote responsible gambling. Read about all of the tools and features available to help you gamble in a safe and controlled way, from self-exclusion to deposit limits. Find out what advice services are available and where to find them. Betting is fun keep it that way.

Why Do People Bet and Gamble?

betting shopWe all take risks every day of our lives assessing rewards relative to what we stand to lose. Gambling is part of human nature and has has been part of human culture since pre-history.  The issue now is we don't just bet for food or resources we can gamble on pretty much anything, anywhere and anytime.  Modern society allows us to place wagers whenever we want and while that might be a great thing for free society it also comes with huge risks, especially for those pre-disposed to addiction.

Betting Sites Refuse To Pay, Limits & User Bans

voidIt is not common but it does happen.  Players and punters can fall foul of betting rules or terms and conditions for a multitude of reasons, which could result in you losing winnings and on occasion even your stake.  Most sites will ban you or limit you if you are caught abusing offers or betting systematically to ensure you win, but what if you've lost out and you think it genuinely wasn't your fault or you didn't have the right info?  Read our guide on why betting companies refuse to pay out.

Why Do Bookmakers Limit Winning Punters?

limitedIf you've ever won consistently with a betting site it is highly likely you may at some point have had your account limited or suspended.  This means you have heavily restricted stake limits and often cannot claim any promotions or use certain features. The practice of limiting users is rife, but what can you actually be limited for and should it even be allowed?  In some countries bookies are forced to take bets up to a minimum threshold and many argue bookmakers are exploiting an already profitable market to make more and more money.

Making a Complaint Against a Bookmaker

Bookie ComplaintsWe are all human and occasionally both we and bookmakers make mistakes. If you feel you feel a gambling operator has made a mistake or that you have made a mistake due to poorly defined terms and conditions then there are procedures in place to resolve these. Licensed bookies are required to take customer complaints seriously with internal procedures and if this fails there are independent services such as IBAS, the ASA and the Gambling Commission that may be able to help. Alternatively For details on complaining to IBAS and what the service is see our IBAS page.

Betting Site ID and Verification

Terms and conditionsWhy do you have to provide identification to an online betting site? Well it comes down to the terms of their gambling licence, licenced bookmakers in the UK are required by law to check that you are over the legal gambling age and that you currently reside in the country. This is designed primarily to protect minors and vulnerable groups while also preventing fraud in the industry.  This helps make the UK one of the safest places to bet in the world. Many betting sites perform ID and verification checks without you even knowing if you register your bank details with them when you join. Read our guide to find out more.

What To Do If A Bookmaker or Casino Closes

closed signUnder the law deposits held with gambling companies must be in a separate account to the main business.  The money however is not protected in the same way that your money in a bank would be and to complicate matters its is up to the operators what level of protection they opt for with your funds.  Therefore if a brand does go bust there is a chance you could lose what you have in your account.  This however rarely happens and even when it does there are signs you can spot along the way that could mean you could get out before it goes under.  Read our article to find out what happens to bookmakers and casinos when they go bust, in the real-world and online.

What Is The Best Value UK Lottery?

lottery ballsEven with the rise of online betting the lottery is still the most bet on single game in the UK.  British people seem to have a special affinity with playing the lottery and can, in fact, play more lottery games than in any other country.  With so many different games available from the standard Lotto to variations such as Thunderball and Hotpicks, international lotteries such as EuroMillions as well as independent lotteries such as the health and postcode games how do you know which offer the best value?  In our guide we've looked at the various games, prizes and your chances of winning to help you decide.

How To Bet Online When Abroad

abroad 2Rules determining whether a UK licenced bookie will let you bet when you are in another country vary depending on licensing, regulation, legality and ultimately whether the bookie chooses to operate in that region.  In this article you can find the best UK betting sites for coverage abroad, details of licencing and other rules that apply, tax laws, using VPN's and an FAQ to betting when abroad.

Gambling Laws Around The World

lawWe get a bad reputation in the UK as a nation of gamblers but in actual fact we have some of tightest regulation in the world.  The UK allows provision of almost all gambling services but under strict licencing rules designed to protect minors and vulnerable people.  Around the world however gambling laws are a patchwork that range from totally illegal to totally unregulated.  Find out how laws in major countries around the world compare to the UK.

Brexit and Betting

brexit and gamblingGambling is actually already regulated and taxed on a country by country level and so Britain leaving the EU should make very little difference in daily life for UK and EU punters.  What is likely to change is how betting companies sell their services around the EU and where they are based, this along with possible post-Brexit tariffs could increase costs that will be past on to punters.  Read our Brexit page where we discuss the potential implications Brexit may have on betting in the UK and the EU,

Related Contingencies

rule 4What are related contingencies and how should you go about betting on related events?  It is often difficult to understand what bets are related and what bets are not, this affects the type of bets your can place and the odds you are given.  For example, you cannot bet on a goalscorer and correct score in the same game as a double bet as these are related, instead you must use a special bet type called the scorecast, see more related contingencies.

When The Bookies Get it Wrong and Lose

winnerWe all know that the house always wins over time, we just hope that we might be one of the statistical anomalies that wins in spite of this.  Therefore when the bookies do get it wrong there is a sense of satisfaction, even if you are not one of the winners.  There have been some high profile incidents over the last 50 years or so where big unexpected outcomes have cost bookmakers a lot of cash.  Read about some of the highest profile incidents of bookies getting it wrong.

The Life Of A Racing Greyhound

greyhound older and retired sleeping on a rugGreyhound racing is not as popular as it used to be but there are still thousands of races each year and tens of thousands of animals involved in racing, in the UK alone. The sport has come in for a lot of bad press over the years on issues such as welfare and what happens to these dogs when they retire.  We've therefore commissioned a vet to detail the life of a modern greyhound in racing and to shed light on the breed, rules and law and veterinary care.

The Decline of Greyhound Racing in the UK

Greyhound Racing Guide 2Once the inner city pursuit of the working classless in the aftermath of world war two Greyhound racing was attended by nearly 35 million people. So what happened to this great spectacle?  Licensing of off track gambling coupled with the slow death of inner cities and the rise of other sports and TV coverage have all contributed to the demise of dog racing. Read about the demise of greyhound racing.

Flapping - Independent Dog Racing In The UK

Greyhound Racing GuideThe majority of greyhound racing is licensed and regulated by the Greyhound Board of Great Britain. Unlicensed independent courses have however always existed and these are known as 'flapping' tracks.  While the standards of unlicensed racing are often more questionable than its licensed counterpart it is not actually illegal. Punters and spectators can go and watch and bet on independent greyhound racing any time you wish.

Places In The UK With The Most Betting Shops

william hill shop in londonLove them or hate them betting shops are now part of almost every British high street but despite the mantra that they are a blight on society there actually only around half the number of shops now than there used to be.  Saying that most of the shops that are left are predominantly placed in poorer areas with stark differences between the most affluent and poorest locations.  In our article we look at the places that have the most bookies overall as well as per capita.

The Life & Earnings Of An eSports Professional

esports event in moscowTo older generations eSports is just a load of nerds playing games and calling it a sport but for millennials eSports is massive with a global following, online and offline.  Professional eSports players can earn millions of dollars from winning a single tournament for the top games such as Dota 2 and and Counter Strike and can command even more in sponsorship.  With leagues of fans in toe top eSports players are celebrities, but what is it like to be an elite player and what demands are there to reach the top?

Amateur & Non-Professional Sports Betting

mult sportsIt is easy to bet on a top Premier League game, every bookie will give you odds, but what about the amateur sports events such as the Olympics or non-professional leagues in football? It is a falsehood that you cannot bet on amateur and semi-professional events, the key is finding a bookmaker that provides markets.  Read our article on how to bet on amateur sports to find out how to place these bets along with the major things to look out for.  We also discuss why bookies are weary of these bet types due to the potential for corruption.

Bet and Match Fixing

match and bet fixingMatch fixing is part of sport and whether we like it or not it happens. Although modern betting sites have many more tools to spot match fixing at the same time there are now many more betting markets available to fix.  These days it is rarely the match result directly that is tampered with but more subtle markets.  Our article looks at famous examples of match and bet fixing along with what happens to your bet if suspicious activity is detected.

Gambling Fraud and Theft

scam alertWhenever there is money involved there is always someone who wants to steal it.  Gambling is entirely about money and therefore it is no surprise that there is a long list of example of players trying to steam from bookmakers and casinos.  There is also no shortage of cases of betting operators themselves trying to fiddle customers for their own gain.  Read out betting fraud article to discover some high profile incidents.

Fixed Odds Betting Terminals (FOBTs)

fixed odds betting terminal with game of roulette being playedWhether you bet in shops or not you will no doubt of seen or hear of fixed odds betting terminals. The devices, that can allow players to stake up to £100 in a singe bet every 20 seconds, have drawn a huge amount of controversy over their effects of gambling addiction and money laundering. Read our FOBT page where we tell you everything you need to know about the machines and the campaigns to control them.  We also look at the point of view of the bookmakers and the economic impact these terminals have locally and nationally.

Betting and Gambling Using a VPN

vpn word blockMany of us now use virtual private networks to access the internet for a variety of reasons.  VPN's allow users added security and give anonymity that make them a useful tool for accessing the web.  From a gambling point of view however the use of VPN's is largely not allowed by betting companies as VPN's are often used to conceal the location people are in, allowing them to gamble pretending to be in the country where they are registered when they are not. 

Trading vs Betting, What Is The Difference?

trading vs bettingIf you watch the news you will see stories all the time of traders recklessly risking money on markets and you might think how is this different to gambling?  A country like the USA largely outlaws sports betting yet you can short sell or hedge on a financial market with far more risk? Look at the damage the financial crash in 2008 did to the world economy, it is easy to argue the affects of trading can be far worse on a large scale than gambling.

Trading on the face of it may seem a lot like gambling but there are many crucial differences, from how it is regulated, how you are taxed on gains and most importantly how much you might stand to win or lose.  It helps to understand trading and spread betting before you get into it.

Betting On Your Kids

chris kirkland playing for englandYou hear all of the time about lucky parents who bet on their child to do something big when they very young at high odds for the wager to come in years later giving a huge windfall.  But just how common is betting on kids and of the many thousands of bets do many actually win? It's not particularly had to bet on children to do things like play for England or win the X-factor, but there are some things to bear in mind before you do bet. We also look at famous examples of big wins.

What Is Courtsiding And Is It Legal?

courtsidingIn basic terms courtsiding is the practice of attending a live event and trying to place a bet on something that happens before it is officially registered.  The practice became know first in tennis, which is where the name comes from, where people would bet on points before the umpire officially registered them, allowing them to back sure-win bets.  The practice is not technically illegal but it is very much frowned upon by bookies and the sports themselves.  Courtsiding is not restricted to tennis and can be done on any pretty much any sport.