Cyclists riding the trails in Dovestone Reservoir near Oldham have discovered potentially deadly boobytraps in areas used by families and cycling clubs.

A message on the Oldham Mountain Rescue Team website said: “A number of deliberate traps have been found around the Chew Plantation near Dovestone Reservoir. These include black cords tied between trees and unstable boulders placed in the landing zone for jumps and drop-offs.

“These traps have the ability to cause lethal injury. Any information relating to them should be passed to the police.”

The traps are reminiscent of an incident on the Bristol-Bath railway path where a cyclist was left unconscious, and his bike stolen, after being brought down by a clothes line strung across the path at wheel height.

World Cup mountain bikers Jack Reading and Tom Braithwaite, who both train in Saddleworth, spoke to the Manchester Evening Post. Jack said: “This could kill somebody – it’s disgraceful. I can’t understand this because I’ve never seen any conflict between cyclists and other people in the area. People are always very friendly.”

Tom said: “It’s absolutely shocking that someone would do something like this.”

Steve Penrice, from The Cyclery bike shop in Uppermill, said: “Riders can go up to 30mph on descents – something like this could decapitate somebody. It’s a worrying situation, it’s very serious. There are teenagers riding up there and they could be hurt.”

Tim Mitchell, secretary of the Saddleworth Clarion Cycle Club, said: “Luckily no one has been injured, but this could have led to a fatality if someone was going downhill at speed. I can’t believe someone would do that. It’s dangerous and a bit sad.”

A GMP spokesman said: “Police in Oldham have been made aware by the local mountain rescue team that informal cycle routes around Dovestone Reservoir had been deliberately sabotaged. The situation will be monitored.”