Political correspondent Tania Branigan is trekking to the Arctic with a team of MPs Read all entries / More on the Arctic challenge
Igloo building. Photo: Tania Branigan
Day three, Ovre Soppero, Sweden: "It's the first time I've seen MPs digging themselves into a hole and actually enjoying it," jokes Stephen, who's on the trip on behalf of Cancer Research.
The group is hard at work building four igloos - their accommodation for the night - under the deadpan instruction of Marcus, one of our local guides. Emily Thornberry and Lib Dem Jenny Willott are tasked with donning snowshoes and tramping around in a circle as the others chuck snow onto them.
Within an hour or so they are on top of a very large, icy mound ... with no obvious way down. "It's a Lib Dem landslide," Emily jokes as Jenny goes head over heels off the heap - only to somersault after her seconds later.
In truth, the MPs are getting on pretty well so far - though there are plenty of jokes at the expense of each others' parties. Lib Dem beard-and-sandal stereotypes, Notting Hill Tories, New Labour spin are all aired at length. Over dinner, they fall into more serious conversation about their political leanings.
"Why are you really a Lib Dem?" Ed and Tobias Ellwood quiz Nick. "Why are you Tories?" he enquires in return.
The questions are half in jest ... but they're off. I seem to remember all the MPs assuring me that they would be "too tired" to talk politics or would think it "too crass" to raise it while on a charity event.
But it's amazing what a few days of enforced familiarity can achieve. I'm betting at least some of the really thorny issues - Labour's health service reforms, say, or the Lib Dem's stance on law and order, or the genuineness of David Cameron's green credentials - will raise their head before this week is out.
Either that, or they were stringing out the debate to delay their night time retreat to the igloos for as long as possible. I read on the net before I came that igloos can be as warm as 16C inside. I can only imagine those are the centrally heated models - ours will reach a maximum of -3C, Marcus predicts. Brrr.
There's a reindeer skin waiting for me now, so I'm off to investigate for myself. I'd been thinking how much I've missed seasons in England - the last few years have had such mild winters - but I've realised many of the things I like about cold weather are actually to do with escaping it, such as cocoa, cashmere sweaters and nice hot baths - none of which are going to be in evidence for the next few days.
But who cares? I've just fulfilled a long-held ambition by seeing the northern lights. They sweep across the sky at astonishing speed, dusting great swathes of light across the blackness. Despite my icy fingers, I was glowing as I watched.
