Security fencing is needed to block off a dangerous, 70ft mine shaft in Cornwall, a couple whose dog fell down it have said.

Bridget and Frank Williams' boxer, Joshua, fell down the shaft at St Day when it opened up on January 16th, the BBC reports. He was rescued by firefighters.

The couple, who own the land, are seeking financial help to put up security fencing and avoid any further incidents.

Mark Kaczmarek, from the Camborne School of Mines, said the shafts could be up to 500ft deep.

He told the BBC that the shafts were probably blocked off around 100 years ago and covered with timber and soil.

"Those timbers are now rotting, and extreme cold and wet weather has put a huge amount of weight on those timbers," he told the news provider.

"All of a sudden you get a collapse."

Mrs Williams said the couple desperately want security fencing to fix the problem, as there are six other sealed-up shafts.

"We've seen the council, the Environment Agency, all sorts of people, but we are responsible and we have no money to do it," she told the BBC.

Last month, temporary security fencing was put up after a series of open mineshafts were discovered in Lancashire.