Police are investigating after a cave diver was found dead in a flooded section of one of England’s largest underground cave networks.

The body of a man in his 40s was discovered at Lancaster Hole, near Kirkby Lonsdale in Cumbria, on Saturday evening.

Emergency services were called shortly before 5pm after the man, believed to be from Lancashire, was reported as being late to resurface during a diving trip.

More than 40 specialists from the Cave Rescue Organisation and Cave Diving Group were involved in the search. His body was found 60 metres (200ft) into the submerged passage by a rescue diver and later recovered.

Lancaster Hole is one of the access points to the Three Counties System – an extensive network of limestone caves that span 53 miles (85km) across Cumbria, Lancashire and the Yorkshire Dales. Since modern records began in the 1920s, 15 cavers have died in the system.

A CRO spokesman said: “As well as searching from the point where the cave diver entered Lancaster Hole, other entrances and possible exits were also searched by team members in case the diver had emerged from the system elsewhere.

“Unfortunately, while conducting an underwater search, a rescue diver discovered the missing man, approximately 60 metres into the cave passage.

“Investigations into the cause of the incident are currently under way on behalf of the coroner by Cumbria police.”

Cumbria police said the man’s next of kin had been informed and his death was not believed to be suspicious.

“The man in his 40s, who is believed to be from the Lancashire area, was visiting Casterton Fell on a cave-diving trip,” a spokesperson said.