Damian Green’s future as First Secretary of State is in doubt after a detective who examined the senior politician’s computer said he found thousands of pornographic images.
Mr Green is already being investigated by the Cabinet Office over allegations that he made inappropriate advances towards a political activist.
Neil Lewis, a retired Scotland Yard officer, said he had examined Mr Green’s computer during a 2008 inquiry into government leaks, and it had contained thousands of thumbnail images of legal pornography.
“The shocking thing as I was viewing it, I noticed a lot of pornography – thumbnails, which indicated web browsing. There was a lot of them. I was surprised to see that on a Parliament computer. I had to take a step back because I wasn’t expecting that,” Mr Lewis, who retired in 2014, told the BBC.
Mr Lewis said he was sure it was Mr Green, who was an opposition spokesman at the time, who had accessed the images.
“The computer was in Mr Green’s office, on his desk, logged in, his account, his name,” the former detective said. “In between browsing pornography, he was sending emails from his account, his personal account, reading documents ... it was ridiculous to suggest anybody else could have done it.”
Mr Green has denied viewing pornography on his computer.
A representative for the first secretary of state said: "It would be inappropriate for Mr Green to comment on these allegations while the Cabinet Office investigation is ongoing, however, from the outset he has been very clear that he never watched or downloaded pornography on the computers seized from his office.
"He maintains his innocence of these charges and awaits the outcome of the investigation."
Mr Green, who has faced calls for him to step down while the investigation is underway, was defended by his colleague, senior Conservative MP Andrew Mitchell.
Mr Mitchell told the BBC: "We need him getting on with the job of helping [to run] the country and not being attacked and blackened in this way."