Five plumbers have been arrested and 600 more are under investigation by HM Revenue & Customs following a crackdown on tax payments in the sector.
Further raids and arrests are expected during the next few weeks in Yorkshire, Kent, Cambridgeshire, Tyne & Wear, Midlands and South Wales.
The action follows a Revenue campaign encouraging plumbers to get their tax affairs in order.
Those arrested so far are alleged to owe up to £150,000 each in tax.
John Pointing, Assistant Director, HMRC Criminal Investigation, said: “These raids and arrests of ‘ghosts’ – people who have not declared income from the work they do – are the culmination of months of work by HMRC.
“We provided a chance for those we have arrested, and the 600 we are investigating, to come forward voluntarily and put things right. These arrests send a clear message that HMRC will take action against those who choose not to come forward and pay the tax they owe.”
Mike Wells, Director HMRC Risk & Intelligence Service, said: “These arrests are just the start.
“HMRC is considering hundreds of further cases for criminal investigation in the plumbing and medical professions. Some people may have thought we were bluffing when we said we have information that we will use to prosecute tax evasion.”
Workers owing tax are invited to come forward under the Plumbers Tax Safe Plan (PTSP) where they will face a maximum penalty rate of 20% on undeclared tax.