Gerry Townrow, 45, was a risk and logistics expert employed by O’Rourke as part of the CLM 2012 delivery consortium.

He was sacked after it emerged that police had found images and video clips on his home computer depicting the abuse of children.

Last week the father of four, whose wife Jayne is divorcing him, was given a non-custodial sentence at Southampton crown court after admitting 18 child pornography charges.

Townrow’s downfall came when his wife of 16 years discovered his illicit downloads and called police.

He tried to delete the files before his computer was seized from his home in Dibden Purlieu, Southampton, but detectives were able to recover the data. His office computer in Stratford was also searched but no wrongdoing was found.

He pleaded guilty to 17 counts of making indecent photographs of children and one of possessing images with the intent to share and distribute them.

CLM told the Evening Standard said that Townrow had no contact with children in his role on site, adding they had taken swift action when told of the police investigation.

A Laing O’Rourke spokesman said: “Mr Townrow was dismissed from our employment for gross misconduct in January having pleaded guilty to the charges that police had brought against him for activity outside work.

“He had been removed from his workplace in September 2010 as soon as we were informed of a police prosecution.”