A police station went into a full-scale lockdown after the son of a Second World War weapons trainer handed in a grenade. 

Chingford Police Station, in King's Head Hill, was evacuated on Monday morning and the area cordoned off when John Chambers, 63, of Chingford, carried in the deactivated grenade wrapped in a carrier bag. 

He had travelled on the 97 bus with his wife Doreen, 76, to the station at around 10.30am after hearing about the Metropolitan Police's two-week weapons amnesty. 

Mr Chambers’ father, Sergeant William Cambers, brought the grenade home in 1946 to Brettenham Road in Walthamstow, where it sat in the wardrobe for 20 years, before being taken to Mr Chambers Chingford home in the late 1960s.

The grenade was drilled to remove the explosive device but still contained a pin.    

Mr Chambers told the Guardian he was surprised the delivery triggered a full-scale operation, including the arrival of the bomb squad.

He said: "I thought there was a dangerous criminal trying to escape, but I soon realised they were panicking over the grenade,” he said.

The police station was evacuated for an hour and explosives officers from the Met's SO15 team were called in.

A cordon blocking off Kings Head Hill to The Ridgeway was removed after the Mills bomb was declared safe at approximately 12:10pm. 

Chief Inspector Jon Simpson said: "We felt it was appropriate to call in the experts and get them to deal with it - in the meantime we took steps to protect our officers, staff and members of the public."

For more on this story, see this week’s Guardian – out Thursday