Both the Department for Education and Employment and the Health and Safety Executive are behind the move, which follows concern that the narrow remit of statutory licences excludes voluntary groups and organisations embarking on adventure activities.

Marcus Bailie, chief inspector of the AALA, said discussions about voluntary licensing had been held with the Scout Association and the Duke of Edinburgh award scheme.

Others who could apply are schools or local groups that undertake adventure-type activities.

Mr Bailie told the biennial conference of the Mountain Leader Training Board: “To make licensing for such groups statutory would have come perilously close to restricting personal freedom. We hope that groups will see the benefits of being licensed and take up the voluntary scheme.”

Conference delegates expressed concern that the licensing scheme was too narrow and a knee-jerk response to the Lyme Bay tragedy.

Compulsory licences are only required for those organisations who charge and deliver adventure services to under 18s, and who offer one of the small number of sports listed and carry out such activities in remote areas.

The conference heard claims that, over the past 25 years, there had been no serious incident apart from the Lyme Bay tragedy - when four children drowned when canoeing from an adventure centre in 1993 - that would have come within the licensing scheme.

It was also pointed out that a recent incident involving a full-scale rescue after six scouts aged 12 and 13 spent a night on one of Snowdonia’s highest peaks in appalling weather did not come under the auspices of the AALA.

Mr Bailie said: “There is concern at just what is outside the scope of the licence. Now the key issues of licensing have been absorbed, people are becoming aware of other aspects.”

He warned the audience of centre owners and instructors that “if we get it right the licensing authority will come down on the side of freedom rather than constraint, but if we get it wrong the Government will impose constraints”.

Roger Payne, president of the British Mountaineering Council, said a political campaign was being planned to try and combat what was perceived in the sport as a lack of awareness among politicians.

He said: “Politicians seem to see only the risk. We want to get across the message about the sport and its value to individuals taking part, its importance to many communities and the numbers involved.

“There is a fear that with the introduction of licensing we are at the top of a slippery slope of legislative constraint and if there is another tragedy restrictions could be extended.”

Ken Wilson, a leading writer about mountaineering, accused those in the sport of being disingenuous in failing to tell local education authorities, individual schools and parents that there was inherent danger in adventure sports.

Mr Wilson said that in seeking to make the sport safe the essential spirit of outdoor activities was being lost. He believed it was important to make clear that even with good training, the proper equipment and good leadership things can still go seriously wrong.

He said: “In the early days in the 1950s there was little doubt in the minds of school masters and youth leaders that to expose young people to outdoor activities would, in some way, be good for them.

“At the same time the pioneers knew that to remove the adventure element would make the activity lack true meaningI The problem with adventure in a sport like mountaineering is that it also includes risk.”

He presumed it was the excitement of the sport which led the Scouts recently rescued from Cader Idris in Snowdonia into their predicament.