Hundreds of guns have been found in a semi-detached house in one of the Metropolitan Police's biggest ever weapons seizures.
Police said "hundreds and hundreds" of guns were found
Pump-action shotguns, M16 rifles, revolvers and antique firearms were among weapons seized during raids on three properties in Dartford, Kent.
Most were found in one house, where a 55-year-old man was arrested on suspicion of supplying guns.
A second man was questioned in linked raids in the United States.
The UK raids were part of an 18-month inquiry into gang shootings in north London and were carried out by Operation Trident, the specialist unit which investigates gun crime in London's black community.
Most weapons, which also included automatic and semi-automatic weapons and thousands of rounds of ammunition, were found at the house, which is believed to belong to a registered gun dealer.
Detectives said some weapons may be legal, others may not.
Weapons were found in every room apart from the bathroom, mounted on walls, left on the floor, or propped up against walls.
Det Ch Supt Kevin Davis, from Operation Trident, said: "This is the biggest firearms haul we (Operation Trident) have ever had.
"The premises raided were used to store hundreds and hundreds of weapons. I have never seen anything like it.
Plain clothes police officers from Operation Trident raided the house
"There are guns everywhere. It will take us at least three days to log it all and bag up the evidence."
Four guns were found at another home while no weapons were found at the third property - business premises, but police said a substantial sum of cash was found at all three.
Another suspect was held in the US state of New Jersey by the Bureau of Alcohol, Tobacco, Firearms and Explosives, which has been liaising with the Metropolitan Police (Met).
Special Agent Rich Marianos said: "We have been, during the last eight months, working in conjunction with the UK authorities on an international weapons trafficking investigation.
"Today in the US, ATF is conducting follow-up investigative efforts in support of the UK's raid in Kent."