UK tax agency sends 81,000 crypto letters

TLDR

HM Revenue and Customs has sent over 81,000 warnings to UK crypto users about suspected unpaid tax, significantly stepping up enforcement after recent bull run gains.

1. HMRC nearly tripled its crypto warning letters versus the previous year, focusing on undeclared gains from the 20222025 bull market.
2. Letters remind users that tax can be due when they sell, swap, gift or spend crypto, with penalties up to 100% of unpaid tax plus interest.
3. From 2027, HMRC will get broader data-sharing powers from offshore firms, making it easier to detect undeclared crypto activity.

Deep Dive

1. Scale Of The Crackdown

UK reports indicate HMRC issued over 81,000 warning letters to people it suspects have unpaid crypto tax in the 20252026 financial year, almost triple the roughly 27,700 letters sent previously.

Officials link much of the suspected underpayment to profits made during the crypto bull run between 2022 and 2025, when coins like Bitcoin saw very large price increases.

The outreach is not one-off: HMRC is clearly treating crypto gains as a mainstream tax compliance issue rather than a niche edge case.

2. How It Affects UK Crypto Users

HMRCs letters remind recipients that taxable events can include selling crypto for cash, swapping one coin for another, giving it away, or using it to buy goods and services.

Failure to declare relevant gains can lead to penalties up to 100% of the tax owed, plus interest, with extra scrutiny for offshore transfers and complex arrangements.

Many targeted holders are described as relatively young and inexperienced with the UK tax system, which increases the risk that casual or high-frequency trading has gone unreported.

3. What To Watch Next

From 2027, offshore firms serving UK customers will be required to share customer information with HMRC, a change the government expects could raise around 315 million by 2030.

That data-sharing should make it easier for HMRC to match exchange records against individual tax returns, reducing the chance that significant crypto gains remain unnoticed.

At the same time, the UK is moving toward a broader crypto regulatory framework by 2027, which will tighten standards for firms and likely increase the volume and quality of transaction data available to regulators.

Conclusion

HMRCs 81,000-letter campaign signals that UK authorities now treat crypto tax compliance as a major, data-driven priority rather than an experimental area.

For crypto users, the practical shift is that activity once assumed to be under the radar is increasingly visible, and future offshore reporting rules will reinforce that trend.

The highest-impact actions for market participants are better tracking of their own trades and a clear understanding of when tax obligations arise, rather than assuming regulators will overlook crypto activity.