Two days in a 30ft-deep crater with only a ticking bomb for company - then Bang...

A GIANT Nazi bomb which fell in a Wiltshire field more than 55 years ago was detonated yesterday in a blast which rocked houses more than a mile away.

Hundreds of sightseers gathered in a safe zone overlooking the field in Chippenham, as army bomb disposal experts carried out a controlled explosion on the 1,000lb device. They had hoped to detonate the bomb shortly after 11.15am, but technical difficulties meant it was not until shortly after 1.05pm.

The blast sent a huge fountain of earth hundreds of feet into the sky and the explosion could be heard for several miles around. More than 1,000 people have spent the past two nights away from their homes after the bomb - dropped in a Luftwaffe raid on the town in 1942 - was discovered on Thursday.

Detonation was carried out after a bomb disposal expert was forced to abandon attempts to defuse the 5ft long device - known as "Fat Boy" - when it began to sink deeper into the 30ft crater on Saturday.

People who gathered to watch the explosion were shocked at its force. Gillian Smith, 44, said: "I expected to hear a bit of a bang but I wasn't prepared for that. I saw a huge pile of dirt fly into the sky and I heard a rumble, but it seemed to take a few seconds for the explosion to reach us.

"It was like standing very close to a huge firework - it really shocked me. I have never seen a real bomb go off before and I don't really want to see another one."

People who were evacuated from their homes were allowed to return yesterday afternoon. Police said the blast caused "very minimal" damage to houses within the evacuation zone. There were no reports of any structural damage to properties hit by shockwaves, and damage is thought to be limited to a few broken windows.

The farmer who first raised the alarm about the bomb said he watched the explosion with relief. Tony Crew, 62, who was a six-year-old boy when the shell was dropped near his parents' farmhouse, said: "Watching it made me think what it would have done if it had gone off at the time. I watched the explosion from a friend's house and also on the television. It gave me a funny feeling and it really made me shiver ... I am very relieved it is all over - it has been a very trying weekend."

The army officer who spent two days trying to defuse the bomb told later how he had hoped to present the empty shell to the school being built on the field. Captain Peter Shields said: "This is a failure as far as I am concerned because we did not manage to render the bomb safe and present the school with the carcass. However, it has produced an excellent result with no damage or loss of life.

"The crater was very cramped - we had some form of safety route to escape if the clay came in, which it did on the odd occasion.

"It was a very difficult decision to explode it because everybody's safety is paramount in an operation like this. In this case, with a nine-metre depth and with a layer of rock above the bomb, we were lucky because we had the ideal conditions to send everything into the air."