How Slots Are Tested and Regulated in Great Britain

Online slots offered to people in Great Britain are regulated by the Gambling Commission, which licenses both the operators that run casino sites and the companies that make the games. Games must meet the Commission’s technical standards for remote gambling and software, and are typically checked by independent test houses before they go live.

This guide sets out the framework in general terms: who does what, what testing covers and how to check a licence yourself.

The Gambling Commission

The Gambling Commission regulates gambling in Great Britain under the Gambling Act 2005. “Great Britain” is precise here: the Act covers England, Scotland and Wales. Northern Ireland has its own gambling law and is outside the Commission’s remit.

The Commission’s job covers:

• Licensing operators and game suppliers.
• Setting conditions that licensees must follow, including technical standards and social responsibility rules.
• Compliance and enforcement, including fines and licence action against licensees that break the rules.
• The public register, listing every licensed business.

Our UK slot rules section collects the rules that apply specifically to slots.

Who needs a licence

Two kinds of business are involved in getting a slot onto your screen, and both need a Commission licence to serve customers in Great Britain.

A game you play at a GB casino may be made by a studio such as NetEnt or Pragmatic Play and run by the operator whose site you are on. Each has its own obligations.

The technical standards

The Commission publishes technical standards for remote gambling and software, often called the RTS. In general terms they cover:

• Randomness. Results must be generated by an acceptably random process, and must not be influenced by anything that should not affect them.
• Fair presentation. The game must work as described, and its rules and information must be available to the player.
• Game information. Players must be able to see how the game works, what it pays and its return to player.
• Player protection features. Requirements such as reality checks and displays of play time and net position.
• Game design. Specific rules for online slots that apply from 31 October 2021, including a minimum 2.5 second game cycle, bans on autoplay, turbo modes and slam stops, and no celebration of returns equal to or less than the stake. See game design rules.

The standards are also the basis for other decisions. On 17 January 2020, the Commission told licensees that bonus buy features break its Remote Technical Standards, and they are not offered on GB-licensed sites.

Independent testing

Before a game is released, it is usually tested by an independent test house. Well-known names in the field include Gaming Laboratories International (GLI), BMM Testlabs and eCOGRA. In broad terms, testing looks at:

1. The RNG. Statistical testing of output and review of how the generator is seeded and used. Our RNG guide explains what is being tested.
2. The game maths. That the probabilities and payouts produce the stated RTP, and that results are mapped correctly from random numbers.
3. Game behaviour. That the game follows its rules, including features, interrupted games and error handling.
4. Compliance with the standards. Spin timing, information displays and other GB-specific requirements.
5. Version control. That what goes live matches what was tested, including when a game comes in several RTP versions.

Testing does not stop at release. Changes to approved games need to go through the process again, and operators are expected to monitor games once they are live.

What certification does and does not mean

Certification means a game is random, works as described and returns what it says it returns over the long run. It does not mean:

• That the game is good value. Every certified slot still has a house edge.
• That you will get the RTP in a session. Short-term results vary widely; see RTP explained.
• That every site offers the same version. The operator chooses from the certified RTP versions; check the information screen.

What a licence means for you

Playing at a GB-licensed site gives you a set of protections that unlicensed sites do not:

• Age and identity verification before play, including demo play, since 7 May 2019.
• Stake limits on online slots: £5 per spin for players 25 and over and £2 per spin for 18 to 24 year olds.
• No gambling on credit cards, since 14 April 2020.
• No reverse withdrawals, since 31 October 2021: once you request a withdrawal, you cannot cancel it to keep playing with the money.
• Deposit limit prompts before a first deposit, since 31 October 2025, and other safer gambling tools.
• Participation in GAMSTOP.
• A complaints process, with access to an independent dispute resolution service.
• Wagering on casino bonuses capped at 10x from 19 January 2026; see bonus rules.

How to check the public register

1. Find the operator’s name and Gambling Commission account number on its website, usually in the footer or terms and conditions.
2. Go to the Gambling Commission’s website and open the public register.
3. Search by account number or business name.
4. Check that the licence status is active.
5. Check that the domain you are using is listed against the licence.

If the details do not match, or there is no GB licence, do not use the site. Unlicensed sites are not bound by any of the protections above, and GAMSTOP does not cover them.

The short version

• The Gambling Commission regulates gambling in Great Britain under the Gambling Act 2005; Northern Ireland is separate.
• Both casino operators and game studios need a Commission licence.
• Games must meet the Commission’s technical standards for remote gambling and software.
• Independent test houses check RNGs, game maths, behaviour and compliance.
• Certification confirms fairness, not value: every slot still has a house edge.
• Check any site’s licence on the Commission’s public register before you use it.

Next guide: Slot Stakes Explained: Coin Value, Lines and Bet Levels