Most of the arrests were in Northern Ireland with one in north London.

HM Revenue & Customs officers searched 31 business and residential properties in Belfast, Co Armagh, Co Antrim and Co Londonderry and two businesses and one private address in Stoke Newington.

An organised crime gang is believed to have created a chain of companies, claiming to subcontract labour for construction projects, with the intent of disappearing before any tax was paid.

Business records, cash and computer equipment were seized during the operation.

John Whiting, Assistant Director Criminal Investigation, HMRC said: “This investigation codenamed ‘Operation Concentric’ is targeting a suspected organised crime gang involved in sophisticated multi-million pound income tax and VAT frauds in the construction industry, and the associated laundering of the criminal profits.

“The frauds are believed to have resulted in the theft of millions of pounds of public revenue.

“Tax fraud and attempts to launder the proceeds of crime are key priorities for HMRC, and we will continue to work with our partners in the Organised Crime Task Force to pursue any individuals or crime gangs believed to be attacking the public purse in this way.”

The 14 are currently being interviewed by HMRC officers and investigations are continuing.