A UK trader sets up a Polymarket account, funds it with USDC, opens the app on a London Wi-Fi connection, and gets a geoblock screen. No trade. No appeal. The same trader switches to Smarkets ten minutes later and places a £50 position on the next UK general election in pounds, from a UK bank account, with a UK-licensed operator. Both venues let you take a view on the future. Only one of them lets you take it from Manchester.
The gap between those two experiences is the entire subject of this guide. Polymarket is a serious venue with deep liquidity on US politics and global news, and the appeal is obvious. But the legal route from the UK runs through different platforms, with different mechanics, different fees, and different markets. Knowing what is actually available, and what each venue is good and bad at, saves you the hour of disappointment that comes from chasing the wrong product.
Why Polymarket itself is off the table from the UK
The short version: Polymarket does not accept UK users. The longer version sits in our piece on whether you can use Polymarket in the UK, but the headline is that Polymarket geoblocks UK IP addresses and UK KYC, and the workarounds people discuss online (VPNs, foreign accounts, stablecoin routing) put your funds and your tax position into uncomfortable territory.
The regulatory backdrop matters here. UK event-based trading sits inside the gambling regime, supervised by the Gambling Commission, and any operator taking bets from UK customers needs the relevant licence. Polymarket has not pursued that licence. So the question is not really "how do I get onto Polymarket from the UK" but "what does the UK actually offer that scratches the same itch." The answer is more interesting than people assume.
Smarkets: the closest thing to a UK-native prediction market
If you have ever used Polymarket and felt at home with the order-book structure, Smarkets will feel familiar. It is a betting exchange licensed by the UK Gambling Commission, headquartered in London, and built around peer-to-peer matching rather than the bookmaker model where the house sets the price.
The commission is the headline feature. Smarkets charges 2% on net winnings, which is materially lower than Betfair Exchange's 2% to 5% standard structure on most markets. For politics, current affairs, and the kind of binary event contracts that Polymarket popularised, Smarkets carries genuine markets: next prime minister, party of next government, by-election winners, US presidential odds, central bank rate decisions. The liquidity is thinner than Polymarket on global news, but on UK politics it is often the deepest book available. Our Smarkets vs Polymarket comparison walks through where each one actually wins.
The thing to know up front: Smarkets is a gambling product under UK law, which means winnings are tax-free for UK residents. That is not a small detail. It is a structural advantage that US event-contract platforms cannot offer their users.
Betfair Exchange: bigger, broader, fiddlier
Betfair is the volume leader. The exchange has been running since 2000, and on major events the liquidity is in a different league to anything else available to UK customers. A Premier League title market on Betfair Exchange will trade hundreds of thousands of pounds across the season. A US election market will trade millions.
The trade-off is the fee structure and the interface. The standard commission starts at 2% but climbs depending on your activity and the market type, and Betfair layers a Premium Charge on consistently profitable accounts that can reach 60% of net profits. Worth knowing about before you build a strategy that depends on a clean edge. The product is also sprawling: thousands of markets, dense menus, and a sportsbook bolted onto the exchange that newcomers can mistake for the real thing. The exchange is the bit that matters for prediction-market-style trading.
For breadth, though, nothing beats it from the UK. Politics, sport, entertainment outcomes, novelty markets on awards and reality TV: if a major event has a probability, Betfair has probably priced it.
Spread betting firms: a different shape of bet, same regulator
There is a parallel UK product that prediction-market enthusiasts often overlook. Spread betting firms like Spreadex and Sporting Index quote a buy and sell range on numerical outcomes (total goals, seats won, runs scored) rather than a yes/no probability. You take a position per point of movement away from the spread.
The payoff structure is closer to a CFD than a binary contract, and the loss profile is open-ended unless you cap it, which makes spread betting riskier than a fixed-stake exchange position. But it is fully UK-regulated, the winnings are tax-free under current rules, and on niche numerical questions it is often the only liquid way to take a view. Our piece on event contracts versus spread betting goes deeper on the mechanical difference.
What about offshore crypto-native venues
This is the part of the conversation where readers usually want a definitive answer and the honest one is uncomfortable.
A handful of decentralised or offshore venues let UK users access markets that resemble Polymarket. Some operate on public blockchains with no KYC at all. Some are explicitly geoblocked from the UK but accessible with a VPN. Using any of them puts you outside the UK consumer protection regime, outside the UK tax-free gambling framework (HMRC's view on offshore unregulated venues is not the same as its view on UK-licensed gambling), and in some cases outside the law depending on how the venue is structured.
The trade is yours to make. Just go in with eyes open. The UK-licensed venues exist precisely so you do not have to make that trade, and on the markets they cover, they cover them well.
Picking the right venue for the question you are asking
The useful framing is not "which platform is best" but "which platform is best for what I am trying to trade." UK politics, by-elections, leadership contests, polling-driven markets: Smarkets is usually the first stop, with Betfair Exchange as the deeper book for the highest-profile contests. US politics and global news from the UK: Betfair Exchange has the volume, though the markets list is narrower than Polymarket's long tail of niche contracts. Numerical outcomes on sport and politics: spread betting firms are purpose-built for the shape. Crypto-native event contracts: not legally available from the UK, full stop, regardless of what a Reddit thread tells you.
The other thing to know is that fee structures matter more than they look. A 2% commission on Smarkets versus a tiered Betfair structure with a possible Premium Charge can change the economics of a strategy entirely. If you trade a lot, model the fees before you model the edge.
iPredicta exists to make that comparison legible. We index event markets across UK-licensed venues and the major international platforms, surface the prices side by side, and write the editorial context that explains why a market is moving. For UK readers in particular, the discovery layer is built to point you toward the venues you can actually use, not the ones you cannot.
Frequently asked questions
Is Smarkets actually legal in the UK?
Yes, Smarkets holds a full operating licence from the UK Gambling Commission and has done since the early 2010s. It is a London-headquartered company, takes deposits in pounds from UK bank accounts, and operates as a peer-to-peer betting exchange under the gambling regulatory framework rather than the financial services framework. That distinction matters for two reasons. First, your winnings are not subject to income tax or capital gains tax under current UK rules. Second, you have access to the Gambling Commission's complaints process and consumer protections, which do not extend to offshore venues. The trade-off is that Smarkets is a gambling product in law, with everything that implies about how the regulator treats it.
Can I just use a VPN to access Polymarket from the UK?
Technically possible, practically a bad idea. Polymarket's terms of service explicitly prohibit UK users, and using a VPN to bypass the geoblock breaches those terms, which gives Polymarket grounds to freeze funds and void positions if they detect the workaround. KYC checks on withdrawals over certain thresholds can catch the mismatch between your VPN location and your real identity documents. Beyond the platform risk, the tax position is genuinely unclear. UK-licensed gambling winnings are tax-free, but HMRC has not given clear guidance on offshore unregulated crypto venues, and treating winnings as tax-free is an assumption rather than a rule. The downside scenario is funds locked and a tax bill you did not expect.
What is the difference between Betfair Exchange and the regular Betfair sportsbook?
The exchange is the peer-to-peer market where users back and lay outcomes against each other, with Betfair taking a commission. The sportsbook is the traditional bookmaker product where Betfair sets the odds and takes the other side of your bet. For prediction-market-style trading, the exchange is the relevant product. It gives you order-book pricing, the ability to lay (bet against) an outcome, and prices that move with real money rather than with a bookmaker's risk team. The sportsbook is fine for casual punters but does not behave like a prediction market. When you open Betfair, make sure you are on the Exchange tab, not the Sportsbook tab, because the navigation does not always make the distinction obvious.
Do I have to pay tax on winnings from UK prediction markets?
No, under current UK rules, winnings from UK-licensed gambling and betting exchanges are not subject to income tax, capital gains tax, or any other personal tax. That covers Smarkets, Betfair Exchange, and UK-regulated spread betting firms. The duty is paid by the operator at source, which is why the consumer side is tax-free. This is structurally different from US event-contract platforms like Kalshi, where winnings are taxable income. The picture changes if you trade through offshore venues, where HMRC's position is less settled, and it changes again if betting becomes your primary trade or profession, which can attract scrutiny. Our UK and US tax guide covers the edge cases.
Which UK venue has the deepest liquidity on US politics?
Betfair Exchange, by a clear margin, on the biggest US political contracts. US presidential election markets on Betfair routinely trade tens of millions of pounds across the cycle, which is enough liquidity to take serious positions without moving the price. Smarkets carries the same headline markets but with thinner books, so larger orders run into wider spreads. Neither matches Polymarket's depth on the long tail of niche US political questions (specific state outcomes, congressional contests, cabinet appointments), where Polymarket's volume is genuinely unmatched and the UK venues simply do not list the markets. For headline US contracts from the UK, Betfair. For depth across hundreds of niche contracts, no legal UK route exists.