A group of engineers were surprised to encounter Otley's notorious bat population whilst attending to a gas leak.

Transco's emergency response team attended a gas leak at Otley Bridge, which runs across the River Wharfe, and discovered its inhabitants of eight years.

The bridge has caused much speculation in Otley due to its winged companions dwelling in a crack in the brick work.

Many agencies have encountered the roost of Daubenton bats dwelling under the bridge and have followed the advice of the West Yorkshire Bat Group when working in the area.

Transco employees encountered the bats last week when trying to locate and repair a gas leak on the main, which runs underneath the busy bridge road.

Transco Network Assistant Bob Harrison said: "We did everything possible to ensure our essential emergency works did not interfere with the colony, by consulting the West Yorkshire Bat Group.

"Protecting the Daube-nton's made the job even more difficult, especially as the gas main is encased in concrete and needed some intricate excavation work, which is all credit to the Transco team."

Ann Best, from the West Yorkshire Bat Group, said: "The bats live in a crack in the brick work under the bridge. The colony feeds on insects living on the surface of the river."

The bats under the bridge are some of Otley's best-known residents, but lately the area has seen an influx of bats to the area.

This summer Pipistrelle bats have been discovered living in a 150-year-old lock keepers cottage in Lindley Wood and in the roof of a Yeadon company.

But before Otley gets a reputation for being a bat haven, Mrs Best says the Wharfe Valley is just one of many places which bats love.

"The Wharfe Valley is very fertile with lots of different habitats of different bats, but it isn't anymore special than the Aire Valley," she said.

"The bats excel where you don't expect.

"In Otley there is the Chevin, the River Wharfe and the bats love all these places. Under the River Wharfe bridge there live Daubenton bats and in other places in Otley there are lots of Pipistrelle bats, which are the most common form."