Over the last few weeks Dave MacLeod and Tim Emmett have been preparing for a first ascent on the mighty cliff of Sron Uladail, Harris.

But this first ascent will be slightly different to most. This coming Saturday Dave and Tim will attempt the new route - accompanied by a BBC production team, and their ascent will be broadcast live on TV.

Dave has been visiting the cliff and checking potential lines on abseil and has found one that he thinks might weigh in at around E8. On his blog from the 8th of August Dave explains:

"I have a route to attempt! The most overhanging section of the entire cliff proved the exception to the rule that I'd encountered so far. Every other line I'd looked at worked apart from short sections that were blank, loose or wet. From a previous abseil from the top of the cliff, looking in from a distance I thought a 12 foot section on theses overhangs also looked devoid of holds. But it was so steep I needed to come back with more gear to back-aid across the roofs to get a closer look. When I did just that on Monday I couldn't believe my eyes! A line of fingertip flakes and slopers leading out across the big roof to gain the next flake system.

The line reminds me of the famous Spanish route Kalea Borroka in Siurana, but even steeper! It's going to be a mind-boggling adventure climbing this thing. I really can't wait for the 28th. Pitch 1 looks like the best pitch of E7 I've seen anywhere. After a hanging belay, the very first move of pitch 2 is the hardest of the entire route. I could only do the move one out of four tries. But it's just a very long reach at 50 degrees overhanging. That's pretty much the same angle as my board so I'll make a model of the crux section to train on. After that it's more hard bloc across the roof to get the next flake system and a spectacular climb up these in the most exposed position imaginable.

I'm not sure yet but this pitch seems like it will be hard E8 or maybe into E9. After that there are three more E6 and E7 pitches through more spectacular terrain. So it was a turnaround of fortunes compared to the last trip. No doubt it wont be the last. But such is adventure climbing!"

Adding more suspense to this top TV drama is the fact that just yesterday Dave reported on his blog that he has split open his ankle, leaving his ability to climb a new E8 in doubt...

"On Monday, while descending the lines after a session on the Sron, a breeze block sized flake at the belay 10 feet above me was levered off by an unusual direction of pull. It dropped straight onto my bare ankle, splitting it open in a 3cm gash down to the bone." commented Dave on his blog.

Lets hope his ankle heals well, the weather gods shine and the route goes well.Good luck to Dave and Tim and maybe if we're lucky Tim will BASE jump off the top - who knows?!

• You can see a trailer for the programme here: BBC Website

Broadcast Information:

• Saturday 28th August:
• BBC2 Scotland and Sky channel 990 1.30pm-7pm
• BBC HD channel 5pm-7pm
• Streamed live on the BBC website
• Available for viewing on BBC iplayer