Scotland's rescue teams deal with up to 350 incidents a year

The two men and a woman spent between 17 and 18 hours on Ben Lawers, near Killin, Perthshire, before they were rescued on Sunday afternoon.

Tayside Mountain Rescue Team leader Alfie Ingram said the bags offered shelter against wind and snow.

The trio, from Durham University, had been caught in whiteout conditions.

Mr Ingram, who assisted with the rescue and is chairman of the Mountain Rescue Committee of Scotland (MRCoS), said: "They did the right thing. They were well equipped.

"All they had used were poly survival bags which cost �5 and they sheltered inside those.

"Survival bags are basic technology and easily go into a rucksack."

Modern technology such as GPS should be used as a complement to basic map and compass Alfie Ingram MRCoS chairman Have your say

The walkers on Ben Lawers were one of three groups who went missing overnight in Scotland.

Two ice climbers were found by search teams in Wester Ross, along with three others in Glencoe.

It came after a 34-year-old man died from head injuries he suffered in a fall in Glencoe on Saturday.

Mr Ingram said the spate of rescues over the 48-hour period were a coincidence rather than the sign of a rise in incidents.

Scotland's 23 teams deal with about 300 to 350 call-outs a year, he said. The figure includes missing persons as well as mountain rescues.

However, Mr Ingram said an over-reliance on new technology was becoming an increasingly worrying factor.

He said: "This is a really important point.

"If you have something new learn to use it before going out on to the hill and not go out and then try to learn how to use it. Modern technology is also dependent on batteries.

"It is important to learn to use a bog-standard compass and map and learn to read the features of a hill by looking at the map.