POLICE dogs have been patrolling a Haslingden reservoir to try to stop trespassing and swimming.

The increased presence at Jamestone Quarry, in Grane Road, comes less than a week after officers issued a warning when they found a group teenagers ‘tombstoning’ off a 30ft rock face there into the 10-metre deep water known locally as the ‘Blue Lagoon’.

Medical experts said jumping into the cold water can cause the body to go into shock and the heart to stop.

James Goodship, 17, from Colne, drowned after playing on a makeshift raft with friends at Lake Burwain in Foulridge last month.

A police spokesman said: “Please be reminded that the quarry is on private land and swimming is not permitted.”