People stay out all night for all sorts of reasons. As sports fans, queuing for the top tickets on centre court at Wimbledon. As hedonists, engaging in all-night drinking binges. As fugitives, on the run from the secret police.
For 31 environmentally committed individuals, their justification for staying out all night was political. Having enjoyed a relaxed Sunday afternoon protesting on the roof of parliament, there was little left to do come nightfall than continue protesting. Still on the roof.
When dawn broke, after a more-than-chilly night surrounding by police gnashing their frustrated teeth, the protestors were still there. True, they were diminished in number. Around 24 less committed individuals had sloped off as things got a little frostbitten. But the hardened core remained, clinging doggedly to the grey roof of the mother of parliaments.
Was it worth it? Did they attract attention? Yes and no. There were headlines to be won, but - like even the best old master exhibitions - they lacked a certain animation. There was little scope for amusement beyond sitting, or occasionally standing, around. No climate change-themed silly dances were on offer. The protestors did not tell jokes. They merely protested.
As nightfall fell for the second time the demonstration slowly drew to an end. Or at least that's what it looked like, from the eyrie of my own office in the Palace of Westminster. The roar of traffic is being occasionally pierced by ragged cheers of defiance, but the writing is surely on the wall for these plucky activists. They've made their point, and at least it'll be warmer in police custody.