In this episode, we speak to Jenny Graham and Calum Maclean about their challenge, which wasn't the furthest, nor the fastest, but the straightest. 

A few years ago, Ordnance Survey found the longest straight line in Britain that didn't cross any paved roads. The line crosses the Cairngorms, and over four days Jenny and Calum walked that line, crossing whatever they came up against. 

On hand were Matt and Ellie Green from Summit Fever Media to record the trip. The result is The Longest Line, a short film about their exploits.

The film will be available to watch as a live premiere on December 28th at 7 p.m. via our Facebook channel and will also be available on YouTube until midnight, December 29th.