Forgive any typos - my hands have thawed but are still aching. It's been a very long, very tiring and somewhat painful day. It was -27C when we set out, and the first 30km or so were hard work - uphill almost all the way.
A night in an igloo isn't the best preparation for a day's sledding, finds Tania Branigan. But while there are Abba songs to be sung, the MPs' mood is holding up.