Hillwalkers attempting to use smartphones to navigate their routes have been blamed for a rise in mountain rescue calls in Grampian over the last week.

Rescuers were deployed four times in four days in the Cairngorms. All 18 people rescued were relying on smartphone-type technology to navigate the hills.

Andy Todd, co-ordinator of mountain rescue in Grampian, spoke out after a joint rescue team from Grampian Police and Braemar Mountain Rescue, supported by colleagues from the Search and Rescue Dog Association, Aberdeen Mountain Rescue and Royal Navy Search and Rescue helicopter from Prestwick, were called out.

Mr Todd said: "I have been involved in mountain rescue for nearly 20 years and, whilst technology can and does play an important part in raising the alarm or assisting navigation, it appears we may be about to witness a marked increase in the complete reliance of smartphone apps to navigate some of the UK's highest mountains.

"What is particularly concerning is that the individuals who are relying on this apparently inappropriate technology often do not possess even rudimentary mountain navigation skills.

"This is putting their lives at risk, and whilst Scotland's mountains are there for all to enjoy, there is a personal responsibility on those who venture into the mountains to do so only when properly equipped and skilled."

Teams were called out once on Friday, once on Saturday and twice on Monday night. The latest rescue came as 14 hillwalkers became stranded in bad weather.

The group raised the alarm on Ben Macdui, the second highest mountain in the country, at about 7pm, after becoming disorientated when they became immersed in fog.

Grampian Police, assisted by members of Braemar and Aberdeen mountain rescue teams as well as a helicopter from HMS Gannet, were involved in the operation.

The group were located just before 11 pm and guided off the hill by foot around 1am on Tuesday.