It sat on a mantlepiece for years undisturbed. Which was probably just as well, because it could have exploded at any time.

Bomb disposal experts were called to a village in the Fens after police alerted them to a live mortar shell.

They took the device away and destroyed it in a controlled explosion.

It is believed that its owner thought the First World War device had been de-activated when he bought it five years ago.

But when his son sent a picture of the shell to a collector, he told them it could still be armed.

A police spokesman said: 'We were called to an address in Wormegay on January 28 after a member of the public reported that she had in her possession what she believed to be a german mortar bomb.

'Upon arrival the EOD did think that it very well could have been a live device and so it was disposed of it with a controlled explosion at around 23.30hrs.'

The lethal Granatenwerfer shell was used in the trenches. It's launcher could hurl it nearly 500yds before it exploded in a deadly hail of shrapnel.