Bats are protected under European law

Natterer's bats have got through gaps in the wall at St Hilda's in Ellerburn, North Yorkshire.

But under European law it is an offence to damage, destroy or obstruct an access used by bats.

The church's vicar, Reverend Dave Clark, says the bats are driving his parishioners away and without a congregation the church would close.

Health hazard

"The little beggars come flying in over the porch door and they fly around in the church itself and have a fine old time during the summer," he said.

As they fly around the inside of the church at night before going out to hunt, the droppings they leave behind mean that keeping the church clean is a full-time job.

"It's a health hazard I suppose," said Mr Clark. "Urine and black muck up and down the walls.

"Bishop Galliford's wife was ill some time ago and she put it down to having taken a service there.

Expert survey

"When you're taking a service of course, you take deep breaths and you're liable to inhale anything that's vaporised around and bat dirt can be part of it."

Worshipper John Grimble said: "If the place is not clean, the congregation won't come and the place will be lost to families who have worshipped here for centuries."

The church stands ona site thought to have been occupied by a monastery founded by St Aidan in 647 AD and there is evidence of a Saxon building below the present nave.

Conservationists at English Nature plan to carry out a survey next month to establish how exactly the bats are getting into the church.