Cwm Idwal. Photo: Photo Mikey Bean.

A seven-hour rescue operation was launched to rescue seven students on a Duke of Edinburgh’s Award expedition.

And their supervisor was airlifted to hospital after falling while searching for the group in Snowdonia last night.

Members of the Ogwen Valley Mountain Rescue Organisation mounted a major search and rescue operation after the group reported to two adults supervising them that they had got lost in thick cloud on the mountains above the Ogwen Valley.

The party, from south Hertfordshire, has successfully traversed Snowdon the previous day and headed for the Glyderau via the Miners’ Track. The seven candidates, on a gold assessed venture, passed Glyder Fach and moved towards Glyder Fawr, but mistook the summit cairn of the Gribin ridge for Glyder Fawr.

They headed west and found themselves descending broken craggy ground, believing they were heading for the Devil’s Kitchen and Cwm Idwal.

The party then split, with two girls making it to the safety of Cwm Idwal and then down to the Idwal car park. The rest of the party radioed their supervisor to tell them of their plight.

Chris Lloyd of the OVMRO said: “However, as the two girls had both the maps, the stuck party could not report their possible location.

“The assessor and climbing friend made their way up and in a break in the cloud saw the party. They walked up into Cwm Cneifion and then scrambled the steep loose back wall.

“Here the assessor took a 20m (65ft) tumbling fall suffering some severe cuts to his legs and arms. Mountain rescue was called at 8.30pm. We deployed a hasty team to try to locate the casualty.

“We asked for helicopter assistance from 22 Squadron RAF Valley. The hasty team was backed up by a main ground party carrying stretcher and ropes. A duplicate party awaited on the landing zone at Oggi Base in case the helicopter could ferry them up to high ground.

“The changing cloud level presented problems in locating the casualty and the evacuation.”

The injured man was eventually winched aboard along with two others and flown down to Oggi Base about 10pm. The casualty was driven down to Ysbyty Gwynedd at Bangor.

Mr Lloyd continued: “Meanwhile the others had to be rounded up and walked off. All were back at Oggi Base for about 3.30 this morning.

“Quite a few lessons learnt by the group and assessor last night!”