Best Online Slots UK

By Dale Shelabarger, Updated:

Looking to learn more about some of the best online slots currently available at UK online casinos? Then this is the place for you. Here at Inside Casino, we offer detailed reviews of a massive range of slots from some of the most revered online casino software providers in the industry. You’ll find unbiased assessments of slot games from the likes of NetEnt, Microgaming and IGT to name but a few. Our aim is to furnish you with as much useful information as possible so that you can get the most out of each online slot.

IGT Slots UK

IGT Slots UK

International Gaming Technology, often shortened to just IGT, is one of the most significant names in the online casino industry. Initially a manufacturer of video slot machines way back in...
Microgaming Slots UK

Microgaming Slots UK

This page contains information on online slots games by Microgaming, one of the industry’s most prolific casino game developers. Established on the Isle of Man in 1994, Microgaming has been...
NetEnt Slots UK

NetEnt Slots UK

Net Entertainment, or NetEnt for short, is one of the leading developers of casino software in the UK. Based in Sweden, this developer is best known for its highly entertaining...
Playtech Slots UK

Playtech Slots UK

This page showcases slots games made by Playtech. This Isle of Man-based firm is one of the most popular developers among online casino operators in the UK. In fact, many...
Progressive Slots UK

Progressive Slots UK

The potential to win life-changing sums of money from a single spin is the hallmark of the progressive jackpot, which is one of the reasons why UK casino players keep...
Video Slots UK

Video Slots UK

Slot machines have come a long way. Originally a physical machine with sizes that were as small as desktop computers to as large as refrigerators, these slot machines relied on...

Best Online Slot Reviews

Our casino slot reviews are organised into a large database which is constantly being updated. In evaluating each slot, we focus on a fixed set of criteria that can prove crucial to the overall enjoyment of the game, not to mention its ongoing success. These include special features, bonus rounds, RTP and responsivity. We also provide background information about all online slots that we review in order to give you the complete low-down on each title – knowledge is power after all!

Types of UK Online Slots

Everybody has their own preferences with regards to slot games. Some of you enjoy playing online slots steeped in Greek mythology. Some of you prefer the bare basics of retro games. Then there are those of you who can’t get enough of jungle-themed slot titles. Whatever you predilection may be, you’ll find reviews on all manner of online slot games at Inside Casino. However, before we delve into the different variants currently on the market, here’s a brief history of this captivating gambling game.

Online Slots - A Brief History

Online slots can be traced back to the late 19th century and derive from mechanical countertop machines once used at US grocery stores. Known as trade simulators, these clumsy contraptions dispensed fruit-flavoured chewing gum – hence why cherry and melon symbols still decorate slot reels today.

Mercifully, these primitive machines were superseded by a raft of new mechanical slots in the early 20th century that offered more sophisticated methods of accepting coins and dispensing prizes. John Lighton’s 3 for 1 slot is a prime example.

Mechanical slots were eventually replaced by electromechanical variants in the 1960s such as the Money Honey. These slot games were operated by a lever (this is why they’re called one-armed bandits) and featured bigger pay-outs of up to 500 coins. Unsurprisingly, they went down a storm on the Las Vegas strip.

Further advancements were made in the 1970s with the introduction of fully-electric slot machines that used electrical circuitry and random number generators to control the reels. It was during this period that video screens were also introduced that mimicked spinning reels - this is where we get the term ‘video slot’ from.

The next major developments came with the introduction of the internet, the relaxation of online gambling laws and the enhancements in internet speeds and connectivity (let’s not forget refined coding techniques either). All of these paved the way for the massive and sudden expansion of online gambling and in turn, the seismic proliferation of online slot games. Because of this relentless progress, we now have all manner of slot variants to choose from. Here’s a run-down.

Classic Online Slots UK

Based on the original one-armed bandits of the 60s, classic slots are often included as part of an operator’s game portfolio. In most cases they consist of just three reels and a single pay-line. But don’t be fooled into thinking that these types of slots aren’t relevant anymore. Their addictive simplicity appeals to legions of gamers the world-over.

Online Video Slots

‘Video slot’ is a catch-all term that describes online conversions of land-based machines as well as all other online games, save for classic variants. While versions of bricks-and-mortar machines tend to feature identical game-play, the newer video slot games often feature hundreds of pay-lines and all manner of special features including free spins and side-games. The modern casino-gamer can’t get enough of these types of online titles, mostly because they offer exciting, feature-laden gameplay.

Examples of Video Slots – Action Bank, Fluffy Favourites, Gonzo’s Quest, Jack and the Beanstalk, Twin Spin, Motorhead, Piggy Riches

Online Progressive Jackpot Games

Progressive slot games represent another growth area in terms of online casino gaming. These versions include uncapped jackpots which increase incrementally every time a player deposits money. The longer the main prize isn’t claimed, the larger the jackpot which of course means some enormous, life-changing pay-outs. The jackpot is often further boosted because many of these slots are linked together by massive networks that pool player stakes. Gameplay tends to be similar to modern video slots with extra features sometimes added on top of a simple base game.

Examples of Progressive Slots - Mega Jackpots: Cleopatra, Mega Jackpots: Golden Goddess, Mega Jackpots: Isle of Plenty, Mega Jackpots: Siberian Storm

Responsive Online Slots UK

Thanks to HTML5, all of the above slot game variants are now available to play across multiple devices. Previously, the use of Flash prevented the smooth operation of casino games on smart devices, but no longer. Developers are now able to write games for a multitude of platforms. Many casino software developers have also converted their old Flash games to HTML5.

Major Online Game Developers

So what about the companies that create online slot games? Well, at Inside Casino we feature games from all of the major software houses. Each one has its own story to tell in the realm of slot game development - read on for further details.

Aristocrat Online Slots

The down-under developer that’s made a name for itself by producing ‘pokies’ for all manner of bricks-and-mortar establishments including clubs, bars and of course casinos. Although Aristocrat distributes an extensive range of games to Australia, the company has also tapped into the enormous US market. Most of its online games are straight-up ports of its land-based slot games

Bally Online Slots

Bally is absolute royalty when it comes to the production of land-based titles thanks to the famed Money Honey machine of the 1960s. Its legacy was enhanced even further in 1994 after it introduced the first touch-screen video slot, Game Maker. While Bally continues to produce land-based games, many of them have been converted for online play as well.

Barcrest Online Slots

Barcrest was founded in Manchester in the late 1960s and began life as a manufacturer of gaming terminals for the UK’s arcades, bingo halls, casinos and pubs. Specialising in fruit machines the company has been subjected to a number of high-profile takeovers by the likes of IGT and more recently, Scientific Games. These days it develops online titles – its most famous offering is the ubiquitous Rainbow Riches trilogy.

IGT (International Game Technology) Online Slots

IGT was founded way back in 1975 and specialised in the production of mechanical slot machines. After the success of its video poker machine in the late 1970s, IGT created what is thought to be the first progressive land-based slot, the Wheel of Fortune – one of the most popular slot games of all time. The 1990s saw the company develop online slots which it has stuck with ever since. As a result, players have at their disposal one of the largest back-catalogues of slot games in the industry. Some of IGT’s most notable titles include Cleopatra, Da Vinci Diamonds and Siberian Storm.

Microgaming Online Slots

Microgaming is a bona-fide online slot specialist that began to develop games in the mid-1990s. In that time it has introduced an endless array of blockbuster slots such as Immortal Romance, Thunderstruck I and II as well as Lucky Leprechaun. The Isle of Man outfit is also renowned for producing progressive games like Mega Moolah and The Dark Night.

NetEnt Online Slots

Scandinavian upstarts, Net Entertainment, have made a name for themselves in a relatively short space of time by producing innovative titles such as Finn and the Swirly Spin as well as progressive games like Mega Fortune. Recently, this award-winning developer has also started to include branded games as part of its burgeoning portfolio, with titles like Aliens and Guns N Roses proving particularly popular among players.

Novomatic Online Slots

Novomatic are another company that once specialised in land-based slots. Their famous Gaminator® cabinet, which includes multiple Novomatic titles, is widely available in bricks-and-mortar establishments in the UK and US. In terms of online slots, Novomatic has a formidable back-catalogue that includes titles such as Book of Ra, Lucky Lady’s Charm Deluxe, Reel King and Sizzling Hot.

Playtech Online Slots

This Israeli gaming firm is one of Microgaming’s main rivals and for good reason. Like their competitor, Playtech has become famous for developing cutting-edge games such as the Three Musketeers and Queen’s Diamond. It also secured the rights to produce Marvel-branded games, releasing a collection of progressive games under that banner including The Incredible Hulk, The Iron Man Series and the Avengers.

Play'n Go Online Slots

Play’n Go is a Swedish casino game developer founded in 1997. It has expanded quickly since then and now has offices in a variety of locations around the world including Hungary and Malta. Distributing responsive, mobile-friendly games (who doesn’t these days), Play’n Go’s game catalogue comprises big-name titles such as Flying Pigs, Mermaid’s Diamond and, um, Leprechaun Goes to Egypt.

Online Casino Slots – Things to Look Out For

While we appreciate that most of you are familiar with the intricacies of slot gameplay, we’ve included a quick run-down of the features that you can expect to see when playing the latest titles – you know, just in case. Some of these are factored into our slot reviews.


Pay-lines are a crucial element of any online slot and are basically the line on which winning combos are made. While old-school retro slots don’t usually include that many, the latest games often comprise hundreds, some of which pay both ways. The majority of slot game interfaces don’t include information about pay-lines in the home screen, unless of course you trigger one. For most games they can be found in the ‘information’ or ‘about’ tabs.


Scatters are high value symbols that are usually signified by a themed animation or graphic. When a pre-specified number of scatters appear on the reels, they usually unlock bonus features of some kind. Information about the number of scatters required to trigger bonuses are often included in a slot’s pay-table.


Wild symbols are another element that can truly enhance game-play for the simple fact that they often substitute all reel symbols and create pay-lines. There include, but are not limited to, sticky wilds, which stay in place after the reels spin, expanding wilds, which spread across all reels, and stacked wilds, which appear vertically.

Bonus Rounds

Along with scatter and wild symbols, bonus rounds are one of the reasons that video slots now dominate the online gambling market. They can be activated during gameplay, sometimes via scatter symbols, and can vastly improve your return.


Before trying your hand at any casino game, it’s well worth making a note of its RTP (return to player). This describes the percentage that any given slot will pay back after 100 credits have been played. Return to player rates are usually lower for progressive slot games for obvious reasons while rank and file slots tend to feature higher RTPs.

Online Slot Volatility

Volatility refers to the size and frequency of the pay-out you can expect from a specific slot game. Slots with high volatility rates pay out larger sums but on a less frequent basis. Accordingly, those with low volatility pay out smaller amounts more regularly.

In addition to RTP, volatility should really be factored in when considering the size of your budget. Those of you with cash-on-the-hip will probably be more attracted to highly volatile slots. If you’re sticking with a smaller budget, then it’s advisable to restrict your play to low volatility games, unless of course you’re dead set on destroying your gambling allowance faster than it takes to boil an egg.

Before we bring this particular gambling treatise to a close, we should stress how important it is to read a slot game’s pay-table. Blindly jumping into a casino game without familiarising yourself with its specific features and nuances means that you’ll be exceptionally well-placed to lose money quickly.  So clue yourself up first before committing any funds. That way you’ll have more fun!

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