A relaxing afternoon in the back garden sparked a full-scale emergency alert when Tim Wittington stumbled on a hand grenade.

Tim, 25, at first thought nothing when he spotted the mud-covered device as he and his brother were digging in the garden of his home in Ringmer Road, Moulsecoomb.

But when he showed the mysterious object to his wife she made a 999 call - and minutes later their house had been cordoned off by police as army bomb disposal experts raced to the scene.

Tim was laying foundations for an extension in his back garden when his younger brother dug up a piece of metal.

Johnny Wittington, a 19-year-old joiner, at first thought nothing of it and tossed it aside.

It wasn't until Tim, 25, showed it to his wife that they realised it was a potentially lethal explosive.

Tim said: "We were having a tea break at about 3pm when my eye caught a piece of metal in the pile of earth that Johnny had dug.

"It was covered in mud, and at first that's all we thought it was.

"I picked it up to have a closer look and called out to my wife, Amy, who was sitting nearby with our baby. Suddenly we realised what it was."

Tim, who is about to start studying to be a social worker at Sussex, found himself staring down at a grenade in his hand.

He said: "I thought, "Flippin' heck, I'm holding a grenade! What on earth do I do?" It was quite a shock. I held it as far away from me as possible, but realised that wouldn't do any good if it went off.

"I brought it out to the front of the house, just in case. I was more shocked than scared."

Amy Wittington, 24, said it took a while to dawn on them how serious it could be.

She said: "Because Johnny had already chucked it to one side and it hadn't gone off we didn't panic, but I took the girls into the house as a safety precaution and then called the police.

"When they said they'd be round immediately I realised how serious the situation was."

Tim said: "The police cordoned off the front of the house. They were very cautious and wouldn't let us near the front garden.

"Then the bomb squad arrived and inspected it. They knew as soon as they saw it it was safe, but they had to take it away anyway. I think it was too old to be live.

"I was a bit disappointed I couldn't keep it as a souvenir, but I suppose there was a chance it could turn up again somewhere in a few years so it was best to dispose of it."

Amy said: "Now that we know there's no danger, it's funny to think the guys had no idea what they'd found.

"I was sitting in the garden with my two-year-old and eight-year-old girls playing nearby and the baby on a blanket by me.

"When the boys took a break Tim came over to me with this thing in his hands saying "Look what I've found". He just thought it was an old lump of metal.

"I suppose it's the last thing you'd expect to find."

A police spokeswoman said: "The army bomb disposal unit retrieved a 'practice grenade' from either the First or Second World War from the garden.

"It was caked in mud so it was hard to date it on the scene, but it was obviously very old. We took advice from the bomb disposal unit who did not feel it was necessary to evacuate the house."