Builders have been waiting for hundreds of the nocturnal creatures, which roost in St Cadoc's church in Llangattock Lingoed, near Abergavenny, to leave for their winter hibernation, before work can begin.

There is a very big colony there and so we couldn't begin the repairs straight away

Jean Prosser, Parish deacon

During the summer, villagers noticed that the church roof had shifted and scaffolding had to be erected to stop it from collapsing.

But nothing could be done to fix the roof until the bats had raised their young.

Now they have left their summer home, workmen only have five months to complete the restoration of the roof, which dates back to the early 1200s.

Parish deacon Jean Prosser said people had started to notice the roof moving.

"So we got an architect out who said it was about to collapse," she said.

"Bats roost inside the roof, where they have their babies.

Hundreds of bats roost in the church

"We had to wait until this month to begin the repairs because this is when the bats go out to hibernate."

A grant of more than �200,000 has been awarded by the Heritage Lottery Fund, Cadw and the Welsh Church Fund, to fund the work.

Three types of bat nest in the church - the Lesser Horseshoe, which is an endangered species, the Long Eared and the Natterer.

Scaffolding supported the roof from collapse

"The bats have been here as long as the church has, and we don't want them to be disturbed by the building work," Jean Prosser added.

"That's why we hope that the builders will be able to carry out the repairs before the bats return in March.

"We want the bats to come back without any disturbance.

"We have put a tent up, so the builders can work in the dry and warm with the weathers that come in winter."