Fire officers failed in their efforts today to save a 12-week-old puppy which had fallen down a 40ft hole.

Sasha, a Staffordshire bull terrier, plunged down a natural fissure on farmland at Cassop, near Spennymoor, County Durham at 2pm yesterday.

A mechanical firm had supplied the use of a digger as a fire crew aided by RSPCA officers carried out a painstaking attempt to free the pup.

The team was carefully trying to shift earth around the hole, at times using buckets to move it manually, so as not to cause a collapse on to the dog below.

John Percival, 43, from nearby Newton Hall, had been walking Sasha with his son Stephen, 20, yesterday afternoon when the puppy fell, and he called 999.

But rescuers were forced to call off the operation after 3.30pm.

A spokesman for Durham and Darlington fire and rescue said this afternoon: ''We are closing down the incident now. The situation is we have been out there all day and last night.

''We took advice from the RSPCA and our officer at the scene had decided that, as we haven't heard from the dog in two-and-a-half hours and the hole seems to be falling in on itself, we are going to have to close it down.''

Mr Percival was too upset to talk this afternoon.