Two construction firms have been handed fines worth up to £400,000 for hiring illegal workers after a dawn raid at a Flintshire mill.

Northern Irish concrete supplier FP McCann was fined up to £225,000 for five contractors found to be working illegally. 

Meanwhile Stockport-based Adana Construction Ltd will have to pay up to £180,000 for employing another four immigration offenders.

Twelve men and a woman were arrested and will be removed from the UK following a 5am raid on the Shotton Mill site on Deeside on Tuesday, March 19. 

They were all working as subcontracted labourers and steel-fixers.

Immigration Enforcement officers descended on the former paper mill – now being turned into a containerboard factory – in response to allegations from the public. 

Seven contractors, from India and Albania, were later taken into custody, while the others were bailed and are required to report to immigration officials.

Officers entered with permission from the site managers, who have since launched an internal investigation.

This operation follows tough action from the Home Office to triple the fines for companies employing illegal workers. 

From February, the civil penalty rose to £45,000 per worker for a first breach, up from £15,000, and to £60,000 for repeat breaches, up from £20,000. 

HM Inspector Ryan Moore, Home Office Immigration Enforcement said: “Illegal working causes untold harm to communities, puts vulnerable people at risk, defrauds the public purse and undercuts honest employers and jobseekers.

“Our teams will do everything in our power to clamp down on this damaging practice and hit those who cheat our laws in the pocket. This operation was a huge success and I thank our officers who executed it expertly.”

Both companies were issued civil penalty referral notices pending a review of evidence from the site visit and company records.