The duo of Andy Kirkpatrick and Calum Muskett are (as far as we know) currently on the ice-encrusted north face of the Matterhorn in Switzerland, after a long untracked approach in fresh snow.

Squatting at Hornli hut with @CalumMuskett - bitter weather but heading up at 5am to try ????? Route (hope his boots are warm!)

— Andy Kirkpatrick (@psychovertical) December 10, 2014

The pair have been coy about which route they are attempting, but with a skill set between them that includes extreme aid soloing (Kirkpatrick) and E9 trad climbing (Muskett), we are putting our money on an attempt at the Zmutt Nose (Gogna-Cerruti Route). This seldom repeated, desperate and direct route involves both high standard free climbing and some sections of aid.

Camped beneath the Matterhorn. It's very cold but the view's phenomenal @psychovertical @Team_BMC @Rab_outdoorgear pic.twitter.com/0tI9UmRTGy

— Calum Muskett (@CalumMuskett) December 9, 2014

We are guessing the pair are going for this climb because back in early October (when conditions were a lot more summery!) it had a repeat - perhaps only the seventh since the first ascent back in 1969 - by the Italian trio François Cazzanelli, Mark Farina and Marco Majori.

Whatever the route these two are attempting we wish them the best of luck, and you can follow their progress on Twitter (unless the climbing gets too hard or they run out of phone battery) and we'll bring you an update after the ascent.

We have another excellent article from Andy K coming up on UKC tomorrow - ten tips on how to stay warm in the winter - let's hope he has shared that wisdom with Calum Muskett prior to this attempt!