The pressure is mounting on non-compliant taxpayers, particularly those with non-UK assets, says law firm Collyer Bristow, which has been told that 66 individuals have been investigated for suspected tax evasion, including a number of high net worth individuals, based on material contained in 11.5m files from the database held by offshore law firm, Mossack Fonseca.

As part of this investigation, HMRC has made four arrests and carried out six interviews under caution.

Collyer Bristow claims HMRC has become more aggressive about what it regards as non-compliance. Recent legislation retrospectively raises the standard of care required of taxpayers in relation to past tax planning, increases penalties and extends time limits for HMRC to take action.

The ‘requirement to correct’ legislation has created a deadline for taxpayers to declare offshore non-compliance by 30 September 2018. If this deadline is missed, HMRC can levy fines of 100% - 200% of the tax due and even greater penalties in some cases, with naming and shaming and potential criminal consequences.

At the same time, HMRC will be receiving a windfall of information about non-UK accounts of UK residents through the new global common reporting standard.

James Badcock, partner at Collyer Bristow, said: ‘The clock is ticking on non-compliance –- taxpayers with offshore assets urgently need to decide if they need to make a disclosure.

‘Even where taxpayers took professional advice on their tax arrangements, they may not have a reasonable excuse in the eyes of HMRC and the courts. Whether or not a taxpayer has been non-compliant, it would be extremely foolish not to go to HMRC before they come to you.’

Report by Pat Sweet