Overseas countries made 1,553 requests to HMRC for information on UK taxpayers in 2025, up from 1,477 in 2024 and a five-year high, as they step up scrutiny on hidden offshore assets, says business advisers and chartered accountants Lubbock Fine*.
Graham Caddock, Tax Investigations Director at Lubbock Fine, says the bulk of investigations target HNWs who are current or former UK residents or who are suspected of having hidden assets in the UK, often through complex investment vehicles.
Other common targets for investigations into UK residents by overseas tax authorities include internationally mobile workers in sectors such as financial services, technology, crypto and AI, who foreign countries suspect might have underpaid tax for periods of time that they are in the UK.
Graham Caddock says: “The UK is a major hub for internationally mobile entrepreneurs and highly paid workers and The City of London is a global centre for wealth management.”
“That makes HMRC a key source of intelligence for overseas tax authorities to identify hidden offshore assets and unpaid income tax.”
“Wealthy individuals holding assets through complex or unusual investment vehicles attract a lot of attention from foreign tax authorities ”
Graham says that as many countries are struggling to close the deficit between their tax revenues and their expenditure they are expected to make more use of tax investigations to close that gap. Inevitably that will mean more tax inquiries opened both overseas and in the UK.
Graham Caddock says that as HMRC collects more data on crypto assets then it is also likely to attract more requests from foreign countries on assets their citizens may have in the UK.
Since 1 January 2026, UK crypto firms have had to collect information on their users who are tax resident in the UK or in a broad range of other countries. Crypto firms will have to start providing that data to HMRC from January 1 2027.
Graham Caddock said: “Foreign tax authorities are concerned that their citizens are using cryptocurrencies to avoid taxes. Once HMRC starts to receive data from crypto firms it seems likely that overseas tax authorities are going to start requesting this data on their tax residents who use UK based cryptocurrency services.”
Graham Caddock says foreign countries sometimes ask HMRC to collect information on their behalf and it is important for those taxpayers to understand their legal rights and what information is reasonably required, and what is not!
He says: “There is a fine line between what information foreign tax authorities can request from UK residents and what they cannot. Taxpayers and especially wealthy individuals must be ready to push back if authorities overstep their mark.”
“It is not unheard of for foreign tax authorities to request information that UK residents are not obliged to provide. Professional advice can help HNWs decide what information they shouldn’t disclose and help them avoid costly tax bills.”
* Based on an FOI showing the number of requests for taxpayer information made by OECD countries to HMRC.
