I'm guessing Corbyn's cross party meeting yesterday deciding to go down the legislative route to stop No Deal rather than the oft presumed VONC route straight after recess, spooked Johnson's junta into action. They want a VONC so they can play the People v MPs election card if they lose it. By proroguing parliament for 5 weeks it severely limits the time to get legislation through before the next recess and not enough time after the Queen's Speech. However, they may have hit the prorogue button in haste according to this tweet... Proroguing now would be a bit futile, since under s3 of the Northern Ireland Executive Formation Act 2019, if Parliament is prorogued by 4 September then it must be recalled within 5 days, for 5 days. Even without my Remainy McRemain hat on, I would always back Grieve to outsmart Cummings when it comes to parliamentary procedure in the battle of the Doms...