BOOBY traps set on a woodland trail popular with mountain bikers are to be investigated as hazards by council officials.

Mountain biker Matthew Stead, of Idle, raised the alarm after encountering a hastily-built two foot wall made with boulders and a log, which was blocking the trail, as he took a sharp turn in Calverley woods.

The 36-year-old, who says he is a responsible rider, crashed into the wall on Friday and was flung over it and his handlebars, badly bruising his back and leg.

"It could easily have been a lot worse and it could be for someone else unless these obstacles are removed and whoever is responsible is stopped," he said.

Mr Stead said he and other mountain bikers in the past months have noticed a number of logs, stones and large boulders appearing randomly across the trail that passes through the ancient woodland and a well-known spot known as the Bombhole.

"It probably started back in the Autumn with the odd obstacle appearing but it's been getting worse and worse as time has gone on. It's that serious now that there is almost a big boulder on every sharp corner and on the crest of hills that you can't see until it's too late. The wall I crashed into on Friday was impossible to avoid - it was a row of stones and a log. I went straight over the boulders, over my handlebars and landed on more boulders," he said.

And he added: "As far as I'm aware it's not illegal to be in the woods. It's also used by dog walkers and horse riders. The majority of us are responsible riders, we will stop or get off our bikes if someone is near."

Mr Stead said he believed whoever is placing the obstacles is an adult doing it with intent.

"They are large boulders so someone is putting in a lot of effort. I think someone has had a run-in with a mountain bike and taken it on themselves to wage war against us by setting up these dangerous booby traps. We need to warn other mountain bikers to be on their guard, otherwise someone will be seriously hurt. It is getting sinister now and it has to stop."

Mr Stead rang the police on 101 immediately after he was hurt on Friday and was told that officers would have a look. In the meantime, Calverley conservative councillor Andrew Carter has called for the purpose-made obstructions to be investigated by council officers.

He said: "Obviously we can’t have dangerous obstructions that can cause serious injury. Leeds City Council holds the management agreement for Calverley Woods and I have asked them to investigate this matter.”