The line, first climbed by sport climbing super-star Neil Carson in the mid-nineties is renowned for being the physically hardest trad route in Wales.
McHaffie top roped the line on two previous occasions before climbing it on his first attempt on the sharp end.
"It is totally safe" commented McHaffie, "but it still feels scary!"
The route was originally graded E8/9 7a (F8b) by an on-form Neil Carson, who was climbing F9a on bolts at the time of his ascent. It is unclear whether Carson placed the gear as he climbed or if he opted to climb the route in a more sporty style with preplaced runners.
James placed all gear on lead as he climbed. The route is adequately protected by old pegs interspersed with good, but small runners. The crucial placement is a size 0 cam which protects the 20ft crux sequence. It is possible to take a 45ft fall on to this cam, which is backed up a few feet below by two tied-off pegs.
"It's more like F8a+," said James, "and either hard E8 or E9, but the pegs are only going to get worse."
Even without the pegs, the grade of the route wouldn't bump up any higher than E9, as the natural protection is adequate, if very hard to place on lead. James elected to skip the peg that would protect the crux as it is in very poor condition and isn't worth clipping.
The route went smoothly, but James did struggle for a moment on a one finger jam with his right hand high on the route, you can see him work his finger-tip into the slot in the video below.
VIDEO: James McHaffie on Mission Impossible
Thanks go to Dave Pickford for the photographs.