Fiennes arives at base camp for Everest attempt

If anyone has proved themselves as tough as old boots it's Sir Ranulph, who having notched up a string of exploratory feats, confounded pretty much everyone in completing seven marathons in seven days within months of suffering a heart attack in 2003. But in his latest challenge there's the added complication of his fear of heights "It is a good idea not to look down, except at your boots." He told the BBC's Breakfast programme this morning via video phone from base camp.

The explorer told the Beeb that he hoped to have started out on the climb in the next two to three days.

Typically for Fiennes this isn't just an exercise in vanity climbing, the aim of the summit attempt is to raise £2m for the British Heart Foundation, with the cash going to a special unit for children with heart disease at Great Ormond Street Children's Hospital. If you want to chip in with the effort from the relative comfort of your desk you can do so here.

We'll keep you posted with how he gets on.