A UNIQUE charity challenge to relive some of the trials and tribulations of the protagonists in the literary classic Kidnapped by Robert Louis Stevenson has been launched.

Starting from Edinburgh, adventurers Alan Rankin and Willie Gibson are to retrace the famous land and sea journey from the Scottish literary classic next year, 130 years after its publication.

The charity challenge will see the duo sail 500 miles from South Queensferry in the Firth of Forth, northwards and around Orkney then down the west coast landing on the rocky island of Erraid near Mull.

From there they will swap sailing garb for walking boots to hike and run the 260 miles back to Edinburgh.

Penned in 1886 by one of Scotland's most famous writers, Kidnapped tells the tale of David Balfour’s kidnapping and subsequent adventure as he is smuggled around the coast of Scotland, surviving ship-wreck, witnessing the infamous Appin Murder before fleeing the Redcoats with Alan Breck Stewart and then on to Edinburgh to claim his rightful fortune.

In 2006 Mr Rankin became the first person to sail and cycle around Scotland and in 2013.

Mr Gibson has competed in more than 20 mountain marathons,.

Mr Rankin said: "Kidnapped is one of my favourite books so to retrace the steps and relive the adventure seemed a good idea and it will be a ‘first’ as we don’t think anyone else has ever attempted it.

"The trip combines my two passions of sailing and being in the hills plus connects with a story I have read more times than I care to count.”

Mr Gibson said: "We will be wild camping and taking accommodation along the way in much the same way as the books leading characters David Balfour and Alan Breck Stewart.”