Counter terrorism officers were called in after a mortar shell was handed in to Sutton police station sparking fears the device would detonate.

80-year-old Roy Walker handed in the device that had at one time been sitting on the family mantelpiece for 10 years before eventually ending up in the shed.

Carshalton Road was closed at around 1.30pm with officers from Sutton police informing nearby workers to stay indoors ahead of possible evacuation plans.

Mr Walker said: "I've never seen so many police officers run so fast.

"I took it into the reception and they abandoned the station straight away.

"They didn't know it wasn't armed.

"I just put it on the counter, it was in a plastic bag.

"I couldn't just walk through Sutton carrying it."

He said he was "surprised" by their reaction as the device had been in the family since the 1940s or 50s.

Mr Walker said: "Nothing's happened in that time.

"It used to be on the mantelpiece when my father had it and I would have given it to my children, if they had wanted it I would have passed it down, but they don't want it, they wanted me to get rid of it."

The mortar had belonged to his father, Ernest, who had brought it home from his time in the Pioneer Corp during World War II.

Having seen there was a "surrender" on arms on television and prompted by his family, Mr Walker decided to hand it in.

He said: "My son said 'you've got to get rid of it at some point', 'you should bring it in' as it's not the sort of think you like leaving around in your shed.

"It wasn't armed but nobody knew that.

"I had it in my shed, being in the army myself, as an armoured car driver, I knew it hadn't been armed as it didn't have a warhead."

After handing the mortar into police staff Mr Walker was taken to another part of the station.

He said: "They were quite nice about it.

"After it was all over I just made my way home.

"My wife, Margaret, 78, wondered where I had got to as I had been a long while.

"I had seen the adverts about the amnesty on tv and thought I'd bring it in.

"I'm glad to see it's gone. It was something we had to get rid of. You never know if somebody broke in and got their hands on it what they would do with it."

The gesture however sparked a full-blown bomb scare in the town with roads being closed and staff told to stay indoors.

Heather Kane, 19, of Choices estate agent, said: "They were going to evacuate our building.

"They spoke to all the shops around here, saying it was possible that we might have to leave."

Ann Wheeler, 48, and the controller at GT Cars, added: "They told us we weren't allowed out.

"They had everybody moved back to the tape.

"There were about four police officers out there and they were escorting staff to their buildings."

A spokesman for Sutton police confirmed that a 1940s mortar shell had been handed in to Sutton police station during an organised gun 'surrender' designed to encourage the public to hand in firearms they may have.

Explosives officers from the Metropolitan police SO15, counter terrorist team were called in and declared the device safe at 2.15pm, just under an hour after it had been placed on the front counter.

Mr Walker, of Wigmore Road, Carshalton, said the device had belonged to his father and had made a point of regularly keeping it clean.

Explosives experts said the shell was a 3in mortar without a fuse of firing pin and was believed to have been used for drills or training.

After being brought into the station, front counter staff were told what it was. However as it was wrapped in plastic bags they could not see it to assess its condition.

Acting Chief Inspector Andy Brittain 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."

After the device was handed in officers set up a cordon blocking off Carshalton Road from the High Street to the High Street junction with Throwley Way.