Detectives from the unit Operation Trident, which investigates “black-on-black” gun crime, said that the guns haul was one of the biggest in the history of Scotland Yard.

It will take days to discover whether any of the weapons kept by Michael Shepherd, a 55-year-old collector and licensed dealer, were illegal or were offered for sale to criminals.

The guns allegedly included M16 automatic rifles, shotguns, pistols and revolvers. Some allegedly had silencers attached to their barrels; others allegedly had been fitted with precision sights.

Police said that they found weapons in every room, except the bathroom, of the semi-detached house in Dartford, Kent, and ammunition rounds lying on the floor.

Many had been stored in the garage, while in the house antique guns were mounted on the walls and ceiling.

Detective Superintendent Kevin Davis, who led the operation, said “hundreds and hundreds” of weapons were found. “It’s probably the biggest seizure of firearms that Operation Trident has had since its conception,” he said.

“The premises were used to store hundreds and hundreds of weapons. I have never seen anything like it. Guns are mounted on every available wall space in the property. There are guns everywhere. It will take us at least three days to log it all and bag up the evidence. Some may be legal, some may not be legal.”

Another officer said: “There was so much ammunition in there that if there had been a fire it would have gone up like Beirut.”

Mr Shepherd is suspected of international gun trafficking and of supplying weapons to drugs gangs. He is well-known in shooting circles as a collector of antique guns, especially Victorian and Edwardian weapons, and is considered to be a gentle and harmless eccentric. His website, which has had more than 250,000 visitors, boasts that he has one of the largest weapons collections in Britain and that he has 850 modern and antique weapons for sale at his home.

The raid, which was carried out by 30 officers at 6.30am yesterday, was linked to raids in New Jersey by agents from the US Bureau of Alcohol, Tobacco, Firearms and Explosives. Police suspect that weapons were smuggled from the United States.

British police also raided a house in Dartford believed to be the home of a relative of Mr Shepherd. They found four more weapons and a substantial amount of cash. A business premises was also searched but no items were removed.

The investigation, codenamed Operation Mokpo, began 18 months ago after a series of shootings in North London.

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