A once-in-a-lifetime charity event on Bingley Relief Road has been scrapped over fears from protests by eco-warriors.

Bingley charities were set to gain about £30,000 from the two-day festival, in which people would get the chance to walk along the new road before it opens later this year.

Bingley's Rotary Clubs, Bingley Harriers and town centre manager David Dinsey spent nine months planning the event.

But on "intelligence" from two unnamed sources, developers Amec have pulled the plug on the carnival, fearing demonstrations from anti-road campaigners.

A statement read: "It is with deep regret that having received information about potential risks to security caused by those opposed to the road scheme and having taken advice from the police, Amec has been forced to cancel the planned Charity Weekend on September 6 and 7."

Amec denied any suggestion that the road would not be ready on time but would not elaborate on intelligence it had received.

West Yorkshire Police denied it had come from them. A police spokesman said the police had discussed the issue with Amec on Tuesday, after the developer had expressed concerns. "The decision to cancel the event was taken by Amec," she said.

More than 20 charities had planned to set up stalls along the road and had organised sponsored walks, a fun run, balloon rides, a funfair and a vintage car rally.

Organiser Gordon Hodgson, of Bingley Airedale Rotary Club, was livid.

"Amec came up with this crazy story about how eco-terrorists are going to run amok on the road among the young children," he said.

"Has anybody heard of eco-warriors disrupting a charity event? It is rubbish. They have got it out of all proportion.

"They say their insurance won't cover it. Ours will. This event has been destroyed by a rumour."

Charly Clark, Amec project manager for Bingley Relief Scheme, agreed it was a "great shame".

"Amec will not allow this to affect our close links with the Bingley community and we plan to continue with our involvement in other local charitable work."

Tickets were due to go on sale on Monday.

Mr Dinsey, who described himself as "absolutely gutted", sent out 180 letters yesterday to people who wanted to bring vintage vehicles.

He wrote: "It's a great shame that a handful of individuals, whatever their politics and reasons, are hellbent on protesting and have placed us in this position."

Frances Bertram had organised a conga and line dance for Bingley and Shipley British Heart Foundation and a wheelchair push for Keighley MS Society.

"They are overreacting. This is ludicrous," she said. "If they cancel it, the eco-warriors would have won, and they haven't done a thing. What can they gain by it? The road has already been built."

Already, 250 people had entered a 10km road race organised by the Bingley Harriers, who expected 400 entrants on the day, and a further 200 were doing a sponsored walk for the Bradford Marie Curie Cancer Care hospice. Hospice fundraiser Brian Curran said: "We were expecting to make thousands from the event. It's a great blow."

Derek Green, vice president of Bingley Harriers, said: "We originally planned the event for July but then it was put back to September. We will be notifying all the entrants."

Ernest Taylor, president of Bingley Rotary Club, who has lived in the town for 73 years, said: "I am disappointed and angry that a few activists can spoil it for everyone.

"Objections to this road began 40 years ago.

"It was Amec's decision, but if it was up to us we would go ahead with it and take necessary precautions.

"It was a great opportunity for Bingley people to raise money for local causes and walk down the road. They will never get another chance."