A cave dating back to the 18th century has been boarded up sparking accusations that canal heritage is being destroyed.

The Devils Den cave at Prestwood, near Kinver has been sealed to protect a bats’ nesting site and to prevent it being used by boozing yobs. It was once a boathouse.

It was carved out of the rock in about 1770 as the Staffordshire & Worcestershire Canal was being built through the Prestwood estate.

The estate was owned by the wealthy ironworking family of Foley of Prestwood House and as a condition of allowing the canal through their estate a boathouse was created in a sandstone cliff. It is believed to have remained in use until the late 1800s when the Foley family sold the estate.

Since then it has been out of use until British Waterways decided to investigate it as a bat roosting site.

The firm has now fitted an oak door at the entrance with a small gap in the top to allow the bats to fly in and out and says it did have permission from the owner of the cave Completelink Ltd.

The Staffordshire & Worcestershire Canal Society, the Inland Waterways Association and the Stourbridge Navigation Trust have all complained to British Waterways.

Staffordshire & Worcestershire Canal Society treasurer Chris Dyche said: “As far as we know the boathouse is a unique structure of the waterways and certainly an historic feature of our canal. We have had a lot of feedback from our 400 members who are outraged that something that has been here for 200 years has a had a nasty wooden door plonked across it.

“If it has been a bat haven for that long, why change it now,” added Mr Dyche, from Platts Crescent Amblecote, who has been a member of the society for 30 years.

British Waterways spokeswoman Nicky Lister said: “The cave was clearly showing signs of anti-social behavior with discarded cans and bottles and drug paraphernalia. With the only access to the cave by the steep cliff above or by water, any attempts to enter could pose serious safety risks.”