Rescuers used buckets to remove earth from the fissure

Sasha, a Staffordshire bull terrier, plunged down a natural fissure on farmland at Cassop, near Spennymoor, on Thursday.

A firm made a mechanical digger available as a fire crew aided by RSPCA officers carried out a painstaking attempt to free the pet.

The team was carefully trying to move earth around the hole, at times using buckets to shift 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, when the puppy fell.

Larger hole

Rescuers began their efforts on Thursday, but were forced to call off the operation as night fell and it became too dangerous to continue. They resumed at first light on Friday.

But a spokesman for Durham and Darlington fire and rescue said that they had failed to gain access to the fissure, and it appeared that the dog had fallen into a second, much larger hole.

He said: "We are closing down the incident now.

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

Mr Percival said: "My son tried to catch her, but she disappeared over the edge of the deep crevice."