Dozing bats are delaying demolition of the derelict Bradford & Bingley headquarters, say owners Sainsbury’s.

Hidden hibernating pipistrelles mean the building cannot be knocked down as planned and must wait for the protected animals to awake in spring, the supermarket giant has told “bitterly disappointed” MP Philip Davies.

Last year, Sainsbury’s said it would level the towering block to create a more marketable level site which it would sell to any business – even rival supermarkets.

The demolition was scheduled to begin in January after Bingley shops had made the most of Christmas trading.

But when Mr Davies requested an update on progress, he said he was stunned to learn of the latest problem.

He said: “I have been chasing up Sainsbury’s to get on with demolishing the old B&B site as they pledged, and so I was bitterly disappointed to hear from them that the work was being delayed due to bats.

“I would not like there to be any suspicion that Sainsbury’s are dragging their feet and I will also be asking Bradford Council to work with Sainsbury’s to help ensure that the work is carried out, within the law, at the earliest opportunity”

A spokesman for Sainsbury’s explained the need to let sleeping bats lie.

“We were made aware of evidence of bat activity had been found suggesting that they are hibernating, so we can’t start anything to March or April at the earliest,” she said.

“In the meantime our experts will go in and try to find out more about the bat activity, which has basically closed everything down until they wake up,” she said.

Bradford bat expert Ian Butterfield said hibernating bats had to be taken seriously as they are protected under the Wildlife and Countryside Act.

And he explained how Sainsbury’s might only have a brief time to demolish the controversial building – due to the sex life of bats: “The female bats feed heavily in autumn, then mate in October before hibernating. They emerge in April, then the females go into ‘maternity roost” in June, so there is only that window of opportunity,” Mr Butterfield said.