The UK’s HM Revenue and Customs sent more than 81,000 warning letters, emails and texts to crypto holders it suspects of underpaying tax during the 2025/26 financial year, according to figures obtained through a Freedom of Information request. That is nearly triple the 27,714 letters HMRC sent the year before.
The correspondence reminds recipients that selling, exchanging, gifting or purchasing goods with cryptocurrency can all trigger UK capital gains tax obligations — not just cashing out to fiat. Penalties for non-compliance can run as high as 100% of the tax owed, plus interest, with steeper penalties still for transfers routed offshore.
The timing traces back to the 2022-2025 bull run, when a wave of crypto holders realized gains that HMRC believes went largely unreported. Neela Chauhan, a partner at UHY Hacker Young — the firm that obtained the FOI data — said the enforcement push is catching traders off guard: “A lot of the traders are young, have had little previous exposure to HMRC and often work under the assumption that HMRC has limited visibility over their activities.”
More Firepower Is Coming
The current wave of letters is only the opening move. HMRC’s own guidance already sets out when a crypto disposal triggers a taxable event, and the agency is due to gain new powers next year requiring offshore crypto firms to disclose customer information directly — a measure officials estimate could raise £315 million by 2030.
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Part of a Global Tightening Trend
The UK’s crackdown mirrors a broader pattern of regulators moving from guidance to enforcement. The SEC has similarly proposed a new Regulation Crypto Assets framework aimed at bringing clearer rules to token offerings, part of a wider shift among major regulators toward treating crypto compliance as a standard extension of existing tax and securities law rather than a gray area.
For UK holders who sat on gains through the recent bull run without reporting them, the message from HMRC is now unambiguous: the letters are only going to keep coming, and the agency's visibility into offshore activity is about to expand.
