The UK's tax authority, HMRC, has issued warning letters to approximately 65,000 individuals suspected of evading taxes on cryptocurrency transactions, more than doubling the number from last year. HMRC plans to leverage data from cryptocurrency exchanges to track tax evasion and will adopt the OECD's Crypto-Asset Reporting Framework (CARF) from 2026 to obtain more detailed user transaction information. Under current UK tax laws, capital gains tax applies to the sale, exchange, or use of cryptocurrencies, while staking and airdrop earnings are subject to income tax.