A London-based trader opens two tabs. One shows Smarkets, where a Premier League title market is quoting 1.42 on Liverpool with roughly £180,000 already matched. The other shows Polymarket, where the same outcome is priced at 71 cents with a few hundred thousand dollars of depth. Same implied probability, more or less. Two entirely different products, regulated by entirely different people, available to her in entirely different ways.
This is the awkward shape of the UK prediction market landscape. Smarkets is a licensed British betting exchange that has been operating since 2010. Polymarket is a global crypto-settled prediction market that does not legally accept UK users. They get compared because they both let you trade a yes-or-no view on real-world events, but the comparison only goes so far before the regulation, the settlement currency, and the market scope pull them apart. For a UK reader weighing them up, the honest answer is that one is genuinely available and one is genuinely not. The interesting question is what each does well when you can actually use it.
The headline answer first
If you live in the UK and want to place a real trade today, Smarkets is the available option and Polymarket is not. Polymarket geo-blocks UK IP addresses and its terms exclude UK residents, a position tied to the FCA's view that its contracts look more like unlicensed financial instruments than regulated betting. Using a VPN to access it is not a clever workaround; it is a route to losing the funds if the account is flagged.
That is the practical answer. The more interesting answer is that Smarkets and Polymarket are not really competing for the same trader. Smarkets is built around sports, with politics and entertainment as adjacent product lines. Polymarket is built around news, politics, crypto, and culture, with sports as an afterthought. A UK user who wants to trade the next general election can do it on Smarkets. A UK user who wants to trade whether a specific cabinet minister resigns by Christmas largely cannot, because that market exists on Polymarket and not on Smarkets.
What Smarkets actually is
Smarkets holds a UK Gambling Commission licence and operates as a peer-to-peer betting exchange, which is the same structural model Betfair pioneered. You are not betting against the house. You are matching with another user who holds the opposite view, and Smarkets takes a commission on net winnings. The commission sits at 2% on most markets, noticeably below Betfair's standard 5%, and that gap is the central pitch.
The product is deepest in football, horse racing, tennis, and US sports, with substantial liquidity on major events. The political book is the more interesting part for prediction-market readers. UK general election markets, party leadership markets, and next-PM contracts get genuine volume during live political moments. Smarkets ran one of the more accurate Brexit referendum books in 2016, and the platform has leaned into political markets as a brand differentiator ever since.
The interface is cleaner than Betfair's, the apps work, and deposits and withdrawals run through standard UK banking rails in pounds sterling. Winnings are tax-free for UK residents under the standard treatment of gambling income, which is covered in more depth in our guide to how prediction market winnings are taxed in the UK and US.
What Polymarket actually is
Polymarket runs on the Polygon blockchain and settles every contract in USDC, a dollar-pegged stablecoin. You fund an account by depositing crypto, you trade in cents from zero to one dollar, and you withdraw in crypto. There is no fiat on-ramp on the platform itself, no UK banking integration, and no path that makes the experience feel like using a domestic bookmaker.
The range of markets is the headline feature. Polymarket lists thousands of contracts spanning US elections, geopolitics, central bank decisions, court rulings, celebrity events, sports, and crypto prices. Liquidity is concentrated at the top of the book. A US presidential election market might carry hundreds of millions in volume; a market on whether a specific UK by-election goes a particular way might carry a few thousand dollars and a spread wide enough to drive a bus through.
The model is closer to a continuous double auction than a sports exchange. Prices update tick by tick, and the mechanics of how those prices translate into implied probabilities are worth understanding before you trade. Our explainer on how prediction market odds work covers the conversion in detail.
For a UK reader the legal position is the binding constraint. The FCA treats event contracts of this type as financial instruments that require authorisation, and Polymarket is not authorised in the UK. The fuller version of that argument sits in our breakdown of whether prediction markets are legal in the UK.
Fees, in plain numbers
Smarkets charges 2% commission on net winnings per market. There are no deposit fees, no withdrawal fees on standard methods, and no spread mark-up beyond what the order book produces naturally. A £100 winning position pays £2 in commission and leaves £98.
Polymarket charges no explicit trading commission. The platform takes its economics through the spread and through gas fees on the underlying blockchain, which the user pays in small amounts on deposits, withdrawals, and certain on-chain actions. The headline fee number looks lower than Smarkets, but the all-in cost depends on the depth of the book on the specific market and on USDC conversion costs at the edges. On a thin market the implied spread cost can easily exceed 2%. On a deep one it can be close to zero.
The honest comparison: fees are not where the real difference sits. The real difference is what you can trade, in what currency, under whose regulator.
Liquidity and market range
Smarkets carries deeper liquidity than Polymarket on UK-specific sports and politics. A Premier League match on Smarkets will have tens of thousands of pounds matched within minutes of the market going live. A UK general election market will run into seven figures of matched volume over the cycle. For anything outside the sports and UK political core, the book thins out fast.
Polymarket is the opposite shape. It has practically nothing on UK domestic sport. Its political book is dominated by US races, US Senate composition, US executive actions, and global geopolitical contracts. The depth on top US political markets is enormous by prediction-market standards; the depth on niche cultural or entertainment markets can be functional but rarely matches the headlines. Why some markets are deep and others are puddles comes down to the structural drivers covered in our piece on liquidity in prediction markets.
If you want to trade the next UK Prime Minister, both platforms list it. Smarkets will quote it in pounds with a UK book; Polymarket will quote it in cents with a global book that may or may not be paying attention.
Regulation, the part that actually decides this
The UK Gambling Commission regulates Smarkets as a betting operator. That means consumer protections that UK users will recognise: ring-fenced client funds, complaints procedures, GamCare links on every page, age verification, source-of-funds checks at certain thresholds. It also means winnings are not subject to income tax or capital gains tax under the current treatment of gambling.
Polymarket sits outside that perimeter entirely. It is not licensed by the FCA, not licensed by the Gambling Commission, and not structured to comply with either. Its 2022 settlement with the US CFTC, which restricted its US offering, is part of why it now blocks US retail users from its main platform. UK access is blocked for adjacent reasons. None of this makes Polymarket a scam. It does make it inaccessible if you are in Manchester.
The practical takeaway is that the comparison resolves itself on jurisdiction before it resolves itself on fees or features. A reader in New York would weigh Polymarket against Kalshi and Robinhood, and our Polymarket versus Kalshi comparison is where that conversation lives. A reader in London is comparing Smarkets against Betfair, with Polymarket sitting behind a fence.
The editorial take
For a UK user looking for a prediction-market product they can actually fund and trade, Smarkets is the answer most of the time. It is licensed, fee-competitive, deepest on the sports and political markets a UK user is most likely to care about, and built around banking and currency that work without crypto knowledge. The 2% commission is genuinely good value against the rest of the UK exchange landscape.
For a UK user fascinated by the wider news, geopolitics, crypto, and cultural markets that have made Polymarket the most-watched prediction venue globally, the honest answer is that the platform exists, the markets are interesting, the prices are widely cited as forecasting signals, and you cannot legally use it. Reading the markets is fine. Treating Polymarket prices as a forecasting input is fine. Trying to trade through a VPN is a way to lose the money rather than make it.
iPredicta tracks UK and global prediction markets across the major venues, including Smarkets and Polymarket, and is built for readers who want to understand what the markets are pricing rather than just where to bet. The platform covers UK political contracts, US event contracts, and the cross-venue moves that tell you when something has actually changed. The Smarkets-versus-Polymarket question is a good example of why coverage has to be platform-aware: the same outcome can be priced differently in two places, available in one and not the other, and only useful if you know which is which.
Frequently asked questions
Can I use Polymarket in the UK?
No, Polymarket does not accept UK residents and blocks UK IP addresses from accessing its trading interface. The position reflects the FCA's view that Polymarket's event contracts function as financial instruments that would require UK authorisation, which Polymarket does not hold. Some UK users discuss accessing the platform through VPNs and offshore wallets, but doing so violates Polymarket's terms of service and risks the account being frozen with funds locked inside. The safer reading is that Polymarket is useful to UK readers as a price signal rather than as a platform to trade on. For the longer regulatory picture, our guide to whether prediction markets are legal in the UK covers the underlying logic in more depth.
Is Smarkets cheaper than Betfair?
Yes, Smarkets charges 2% commission on net winnings against Betfair's standard 5%, which is the central pitch of the Smarkets product. The gap matters most for high-volume traders, where the commission difference compounds into a meaningful annual figure. Betfair carries deeper liquidity on most sports markets, particularly horse racing and major football matches, so the cheaper Smarkets commission is sometimes offset by wider spreads or shallower books on niche events. The honest comparison is that for casual political and major sports betting, Smarkets is meaningfully cheaper. For professional sports traders who need the deepest possible book, Betfair's liquidity often justifies the higher commission.
Do Smarkets and Polymarket offer the same markets?
No, the two platforms have almost entirely different market ranges with only narrow overlap on major political events. Smarkets focuses on UK and global sports, UK politics, and a smaller selection of entertainment and current affairs markets, all denominated in pounds. Polymarket focuses on US politics, geopolitics, central bank decisions, crypto prices, court rulings, and culture markets, denominated in USDC. The overlap mostly sits in headline political contracts, such as next US President or next UK Prime Minister, where both venues list a market but price it for different audiences. For everything else, choosing between them is less about preference and more about which platform actually carries the market you want to trade.
Are Smarkets winnings taxable in the UK?
No, Smarkets winnings are not subject to income tax or capital gains tax for UK residents, under the standard tax treatment of gambling winnings in the UK. HMRC does not treat profits from licensed betting exchanges as taxable income, regardless of how large or how regular those profits are. The treatment relies on Smarkets being a licensed betting operator under the UK Gambling Commission, which it is. The picture is different for Polymarket-style crypto-settled platforms, where the involvement of crypto assets potentially brings the activity inside the capital gains regime even before you reach the question of whether the contracts themselves count as gambling. Our tax guide covers both sides in detail.
Which platform is better for UK political markets?
Smarkets is better for UK political markets in practice, because UK users can actually trade on it and because the platform attracts genuine UK political volume. Smarkets ran a widely watched Brexit referendum book in 2016 and has continued to position political markets as a core product, with meaningful liquidity on general elections, party leadership contests, and next-PM markets during live political windows. Polymarket lists some UK political contracts, but liquidity is thinner, the market range narrower, and UK users cannot legally access them anyway. For reading the market consensus as a forecasting signal, both are worth watching. For actually placing a UK political trade, Smarkets is effectively the only mainstream option.