Extreme pornography found on the Commons computer of First Minister of State Damian Green was made illegal just a few weeks after it was discovered by police in raid on Green's office in November 2008.

Laws regarding the possession of violent, hardcore porn were changed on 26 January, 2009, eight weeks after the raid. The Sun reports that some of the images found were so extreme the police sought advice from the Crown Prosecution Service (CPS) about whether to press charges.

There were no grounds for prosecution given the raid took place before the law was changed. It's not clear who was responsible for downloading the material.

A source told the tabloid: "Porn was being accessed on an almost virtual daily basis. Police were told nothing could be done.

"Quite simply, it was not illegal to be in possession of extreme images before January 2009. If the raid had happened a few weeks later it would have been."

The raid was conducted as part of an investigation into government leaks.

Green insists he was not the one who downloaded the images, and doubled down on this in a statement sent to The Sun: "As I have said throughout I did not put or view pornography on the computers taken from my office."

The change in the law was made after a four-year campaign led by the parents of 32-year-old Jane Longhurst, who was murdered by a man who was found in possession of violent images of simulated murder and rape.

In January 2009, it became illegal to access porn that featured life-threatening acts (simulated or not), depicted sex with animals or corpses, or involved injury to a person's genitalia.

Green, who was shadow immigration minister at the time of the raid, has been under pressure to resign since the story was reported last week, and is now the subject of a Whitehall investigation into his conduct.

The investigation was ordered by Prime Minister Theresa May after Green was accused of sexual misconduct by journalist Kate Maltby, an accusation he has called "untrue and deeply hurtful".