UK tax authority escalates crypto warning campaign

TLDR

The UK tax authority HM Revenue and Customs (HMRC) has sharply escalated its crypto warning campaign by sending over 81,000 tax alerts in one year.

1. HMRC issued 81,172 crypto tax nudge letters in 2025/26, about triple the volume two years earlier, signalling a more aggressive stance on undeclared gains.
2. The authority treats many common crypto activities as taxable, and penalties can reach 100% of unpaid tax plus interest, making poor recordkeeping a real financial risk.
3. New data sharing rules for UK and offshore platforms will give HMRC much clearer visibility in coming years, so assumptions of anonymity are increasingly unsafe.

Deep Dive

1. Scale Of The Warning Drive

HMRC sent 81,172 warning letters, emails and texts to UK crypto investors in the 2025/26 tax year, up from 64,982 in 2024/25 and 27,714 in 2023/24, a sharp multi?year escalation in outreach efforts. These messages are nudge letters, asking recipients to review their tax position rather than confirming an active investigation, but they target suspected underreporting linked to gains between late 2022 and 2025 as prices recovered. This pattern shows HMRC now sees crypto tax gaps as material rather than niche, and is willing to run large?scale campaigns to close them.

The surge is documented in HMRC figures released via freedom of information requests and summarised in community reporting on 81,172 tax warning letters.

2. Practical Impact For Crypto Users

HMRCs guidance treats many crypto actions as taxable disposals for Capital Gains Tax: selling for pounds, swapping one token for another, spending crypto on goods or services, and most gifts, with exceptions for spouses, civil partners and some charities. Gains must be calculated in sterling with acquisition costs deducted, rather than simply using transaction values.

Separately, crypto received via employment, mining, staking, lending or certain DeFi arrangements can be subject to Income Tax and National Insurance, with later disposals also triggering capital gains calculations. Penalties for unpaid domestic tax can reach 100% of the amount owed plus interest, and offshore cases can attract higher penalties, reflecting HMRCs view that deliberate concealment should carry a significant cost.

3. What To Watch Next

From 1 January 2026, UK crypto service providers must collect detailed customer and transaction data under the Cryptoasset Reporting Framework, with the first reports on 2026 activity due by 31 May 2027. This regime, described in coverage of the Cryptoasset Reporting Framework, enables HMRC and other tax authorities to share information and is expected to raise hundreds of millions of pounds by 2030.

HMRC also runs a Cryptoasset Disclosure Service that lets users voluntarily report past issues before enforcement escalates. Longer term, HMRC is expected to gain more tools to compel data from offshore platforms, making it easier to match trading activity against tax returns and identify gaps.

Conclusion

HMRCs expanded crypto warning campaign is less about inventing new taxes and more about using large?scale messaging and upcoming data sharing to enforce rules that already exist. For UK crypto users, the practical shift is that previously informal or poorly documented trading is now more visible to the tax authority, so accurate records and proactive review of past returns matter much more than in earlier cycles.