Following the leak of the Panama Papers, 66 individuals have been investigated for suspected tax evasion, including a number of high net worth individuals, a spokesperson for Collyer Bristow said.
Further, HMRC has made four arrests and carried out six interviews under caution.
Collyer Bristow is a London-based law firm providing advisory, transactional and litigation services to commercial organisations and wealthy individuals and families.
The spokesperson said that data leaks and breaches such as the Panama Papers often turn out to be a boon for HMRC, enabling it to collect substantial amounts of extra tax.
They said a raft of initiatives have now been introduced following the data leaks and hacks that have increased the pressure on non-compliant taxpayers, particularly those with non-UK assets.
James Badcock, partner at Collyer Bristow, said: “The clock is ticking on non-compliance, taxpayers with offshore assets urgently