Chris Mason: All eyes on Downing Street - what does the PM say, and when?

Keir Starmer is under heavy pressure from his own party and may announce his plan to step down as prime minister imminently.
Andy Burnham’s big by-election win has reignited Labour dissent and pushed him to the front of the pack as the likely successor.
Labour is debating a fast, internal replacement process versus a wider contest — a new leader could be in place within days or weeks.