The Tories shouldn't get an opportunity to oust Boris and then undergo a full leadership campaign.
Parliament should be dissolved (surely her Maj has this power and now the motive!) and a General Election set for the end of March.
Javid was quite clear this morning that the voters in Bury South (and by extension the country) voted for Boris and not individual MPs, therefore if he goes then its only right and proper that the public get a say.
tbh I'm sick of having PMs put in place who aren't elected into position. Whether it be Brown, May, Boris or looking