Every UK forex broker must be authorised by the Financial Conduct Authority (FCA) before it can legally solicit UK retail clients. That authorisation is the single most important thing to check before opening an account — everything else (platform features, spreads, bonuses) is secondary to it.

What FCA authorisation actually guarantees you

FCA-regulated brokers are required to:

• Segregate client funds from the firm’s own operating capital, so your deposit isn’t company money.
• Participate in the Financial Services Compensation Scheme (FSCS), which covers eligible claims up to £85,000 per person if the firm fails.
• Follow the FCA’s retail leverage caps: 30:1 on major currency pairs, 20:1 on minor pairs and gold, 10:1 on commodities other than gold, and 2:1 on cryptoasset CFDs.
• Provide negative balance protection, meaning you cannot lose more than your account balance.

None of this is marketing — it’s the legal baseline every FCA-authorised broker must meet. You can verify any firm’s authorisation status yourself on the FCA Register before depositing a cent.

FCA-regulated brokers worth shortlisting

• IG Group — the UK’s largest retail broker, with spread betting available (profits from spread betting are exempt from UK Capital Gains Tax and Stamp Duty for most retail traders — check your own tax position, this isn’t universal).
• Pepperstone — ECN-style execution across MT4, MT5, and cTrader, generally tighter spreads suited to scalping-style strategies.
• CMC Markets — its Next Generation platform is well regarded for charting depth and order types.
• OANDA — no minimum deposit requirement and strong built-in charting tools, a reasonable starting point for smaller accounts.

Spread betting vs. CFDs — the UK-specific choice

UK residents have access to a product most other jurisdictions don’t: forex spread betting, which (for most retail traders, subject to individual tax circumstances) sits outside Capital Gains Tax and Stamp Duty. CFDs remain subject to CGT. Which is better depends on your trading frequency, position size, and personal tax situation — this isn’t financial or tax advice, and if the amounts involved are meaningful, a conversation with an accountant is worth more than any broker-review page.

What actually separates a good broker from a bad one

Once FCA authorisation is confirmed, compare: execution model (market maker vs. ECN/STP), typical spreads on the pairs you’ll actually trade, withdrawal speed and any withdrawal fees, and how responsive support actually is — open a demo account and test a support query before funding anything.