A knife amnesty was brought in on 24 May

Among the weapons recovered were axes, a samurai sword, and a 24-inch machete, police say.

People can hand in knives without penalty during the amnesty, which began the week after Kiyan Price, 15, was killed outside his school in Edgware.

Nationally more than 10,500 knives and weapons have been handed in.

The amnesty follows several high-profile stabbings, including the deaths of special constable Nisha Patel-Nasri, in Wembley in May, Kiyan Price in Edgware one week later, father-of-three Barry Wilson in Bristol and 19-year-old Tom Grant on a train in Cumbria.

'Dangerous weapons'

In London, Met figures show 41% of robbers with knives are aged between 15 and 18.

Nearly one in five victims of violent incidents involving knives are from the same age group.

Lynn Costello, co-founder of Mothers Against Murder and Aggression, told the BBC: "I think the idea is to get people to realise sometimes what dangerous weapons they have got in their houses.

"And then anybody caught afterwards, they've had their chance to get rid of them."

But Kevin Everard, director of Be Safe, which deals with children and knife crime, said he was not convinced the amnesty would have long term benefits.

"Unless you are changing people's mindsets, making attitudinal changes to young people, then they can go and replace the knife."