The Walpole Court bats have been formally identified thanks to the trained ear of a professional bat lover.

John Tovey, of the London Bat Group, joined a group of bat watchers at Walpole Court, in Twickenham, to help identify the species of bats believed to be living in derelict garages on the site.

Although the dedicated team of bat watchers had initially believed the bats were of a rare species, Mr Tovey identified them on Monday night as members of the Pipistrelle bat family, common in England.

Joanne Hope, who has been carrying out nightly bat watches, said: “He was extremely knowledgeable and I know that we all learned quite a lot more about bats and their habits and habitat as a result.

“Of course, while we would have been overjoyed if our bats were a rarer species, all bats are protected and so the position with respect to our campaign to protect their roost and highway remains intact.”

It is feared that the bats face losing their homes after planning permission was granted for the largely abandoned garages to be knocked down and replaced by six new flats.

A group of residents from Carpenter’s Court, which backs on to the garages, have been out every night over the past month to monitor the bats and their use of the site, and hope to use the information to stop the development.

Their belief that the bats may also be using the area to give birth to their offspring was supported by Mr Tovey.

Ms Hope said: “Mr Tovey explained that the area behind Walpole Court, including the garages, is currently an attractive environment for the bats to roost and feed.

“He noted that the maternity wing is almost certainly nearby and asked me to forward copies of our bat diaries for review.”

The group intend to carry out their bat watches until the end of September and then start again from mid to late April when the new season begins.

Mr Tovey said: “We had a small group of soprano pipistrelles come into the garden shortly after dusk.

“They were foraging and stayed and fed on insects for about 10 minutes before moving away.

“It was really nice to see the enthusiasm of the residents for their bats.”

Steve Mitchell, of developer Rich Architects, said that a survey of the area was to be carried out by the council and they would be contacted with the findings.