It's all about politics and probably an element of self-interest now, though. Public perception doesn't actually matter in our system until the next election, w

It's all about politics and probably an element of self-interest now, though. Public perception doesn't actually matter in our system until the next election, whenever that is. So, if opposition MPs want to put that off for another three years, everyone currently sitting as an MP keeps their seat by default, the Tories are still in charge but still only with a narrow working majority, and those in opposition parties have only three years to wait for another shot after cleaning house instead of five years. I'm not sure whether that sort of rebellion is a realistic prospect given the views expressed so far today, but I think it would be a rational position for opposition MPs to take given the current unpopularity of both Labour and the Lib Dems among the general public.