Parminder Sidhu, 29, unemployed of Coldharbour Lane, Hayes, Middlesex, was arrested by London’s Metropolitan Police Serious and Organised Crime Command on April 8 2009.

His arrest was part of a wider intelligence operation targeting violent individuals involved in drugs and firearms trafficking in west London. Detectives knocked on Sidhu’s door and asked Sidhu and another male whether there were any drugs, firearms or large amounts of cash on the premises.

They said not, but a police dog handler and dog searched the address and in Sidhu’s upstairs bedroom officers found a dark metal revolver hidden in a carrier bag in a drawer under the bed.

Sidhu admitted it was his but said it was a toy he had been given to keep an eye on. He said he had had it in his possession for “a week or two” and that his friend had got it “from an army shop”.

Forensic examination confirmed it as a firearm defined by Section 57(1) of the Firearms Act and believed to be a converted Brocock revolver.

Detective Inspector Steve Ellen from the Serious and Organised Crime Command said: “Possession of a gun carries a minimum term of five years. This case is testament to the fact that ignorance is no defence.

“This was clearly a dangerous weapon and not a toy. The Met police are committed to targeting anyone believed to be in possession of a lethal weapon.”