More than 1,300 imitation firearms were recovered during the Metropolitan Police's gun surrender.
The advertising campaign featured an invisible man handing in a gun
The weapons handed in include copies of an AK47 rifle and a Magnum handgun, plus 61 real guns.
Also surrendered during the four-week initiative in January and February were 225 knives or offensive weapons and more than 152 rounds of ammunition.
About half of all London's gun-related crime involves imitation firearms, a police spokesman said.
Replica firearms involved in crimes including robbery have either been converted to fire live ammunition or they look so realistic they are indistinguishable from real guns, according to the Metropolitan Police.
During the initiative which ran from 21 January to 17 February, an advertising campaign targeted 10 to 25-year-old males and their family members, friends or partners.
1357 imitation firearms
61 real firearms
13 CS spray canisters
64 starting pistols
225 knives/offensive weapons
37 BB guns
Over 152 rounds of ammunition
Officers also visited shops to make sure they were following new legislation surrounding the sale of replica guns. Test purchases will be carried out at shops suspected of supplying weapons illegally.
Met Police Commissioner Sir Ian Blair said: "Every gun handed in is one less that can be used for violence and intimidation."
The maximum sentence for carrying an imitation gun in a public place without reasonable excuse or lawful authority has been increased from six months to 12 months.
This applies to BB guns, blank firing pistols, cap guns, collectibles, airsoft guns, airguns and other items that resemble a gun.