Crime gangs are resorting to old-style handguns from conflicts such as the Second World War after the success of police raids on suppliers, a Scotland Yard detective said today.

Gangsters are exploiting a “grey area” which means antique or old weapons owned by legitimate firearms dealers are being passed on to street gangs.

Detective Inspector Paul Dorey, of the Yard’s Trident Gang Crime Command, said police had seen an increase in seizures of older firearms, particularly from the First and Second World Wars, in the last few years.

“These type of guns are supposed to be kept as curiosities but we are stopping gang members in the street with them and they are clearly not putting them on their mantelpiece,” he said.

“But it is one thing for a retired soldier to have an antique firearm on display in their front room as opposed to a gang member carrying it in a man bag in a London street.”

Mr Dorey called for tighter controls and safeguards on the supply of guns by registered firearms dealers. His comments came as an illegal armourer was jailed for eight years after police found an antique handgun in the glove box of his car. Thomas Keatley, 28, said he had bought the Forehand & Wadsworth .38 revolver from a registered dealer in Kent, claiming it was legally held.

But when detectives raided his lock-up garage they found a factory for home-made guns as well as hundreds of rounds of ammunition. Detectives believe he was supplying guns and bullets to criminal gangs in London.

Analysis of his bank account showed he was assembling guns from components he had bought online from the United States and Britain.

Keatley pleaded guilty to three counts of possessing handguns and ammunition and was jailed at Maidstone crown court. Detectives say underworld armourers are making ammunition for obsolete weapons, which have been re-activated.

In recent years they have seized dozens of guns including Smith and Wesson revolvers, Lugers and British Bulldog revolvers. Mr Dorey added: “Trident has successfully targeted not only gunmen on the street over the past years but the gun suppliers at source. The result has been a dramatic decrease in the number of shootings in London.”

Figures show they are down by 29 per cent in the last six months compared with the same period last year.

Handguns in the UK have been banned since 1996 with the only exceptions being for antique weapons and those used for the humane destruction of animals.