Chris Mason and Alex Forsyth talk it all through with Adam Fleming. What will happen this week? How does the leadership race work? And how much support has each candidate got?
Rishi Sunak says he is in the race to be the next Conservative leader (and prime minister), Business Secretary, Jacob Rees-Mogg, tells the BBC that Boris Johnson "will clearly stand" and Penny Mordaunt (who had already declared she was going to run) says she regrets Liz Truss's mini-budget.
This emergency Newscast was made by Sam Bonham. The studio manager was Matthew Cadman. The senior news editor was Jonathan Aspinwall.