INSTRUCTORS who led a tragic school caving trip have received the backing of the Government inspector in charge of outward bound centres.

Marcus Bailie, head of inspections at the Adventure Activities Licensing Authority (AALA), said there was no evidence blaming leaders for the death of 14-year-old Joseph Lister.

The comments came after it emerged flash flooding may have trapped the Tadcaster Grammar School pupil in the cave in Nidderdale, North Yorkshire.

The teenager, from Steeton, near Tadcaster, vanished during an expedition with ten other pupils organised by Bewerley Park Outdoor Centre, near Pateley Bridge, North Yorkshire, on Monday.

He was found by rescuers, but later died in hospital with his parents at his bedside.

Witnesses said the River Nidd, which flows past the entrance of Manchester Hole, rose 2ft in an hour on Monday.

Further upstream, water was seen being blown over Scar House Reservoir dam by gale-force winds.

Experienced cavers say the system can flood to the roof after heavy rainfall.

Bewerley Park was visited by AALA inspectors, who issue licences to outward bound centres, in February.

Mr Bailie said staff had every confidence in the skills of the leaders following their visit. "There's no evidence to suggest we should modify that confidence now," he added.

"Of course, once the investigations has been completed, we will look at any lessons that can be learned and try to act on those, not just for Bewerley Park but other centres offering similar activities."

Joseph's parents, Martin and Paula Lister, have spoken of their "total devastation".

North Yorkshire County Council, which runs Bewerley Park, said yesterday the centre would remain closed until at least the end of next week.

Two schools from the north of the county have had visits postponed and a residential course, planned for this weekend, has also been called off.

A council spokesman said: "Our counsellors are still at Joseph's school and will remain so as long as they are needed. A number of students have found it very beneficial to talk through the whole scenario with people."

A book of condolences has been opened at the school and a lasting memorial to the teenager is planned.

A post-mortem examination carried out yesterday proved inconclusive and further tests will be carried out.

Justin McCracken, acting chief executive of the Health and Safety Executive (HSE), said last night he remained a supporter of outdoor education, despite Monday's fatal accident.

He said: "Thousands of school trips take place every year without incident.

"We would not discourage such trips as the benefits to pupils can be immense. Serious incidents, such as the one in the Yorkshire Dales on Monday, are extremely rare."

The HSE and North Yorkshire Police have started a joint investigation.