This is devastating for Angela Rayner.

Having overcome a difficult upbringing and personal adversity to climb the heights of the Labour Party and become only its second ever deputy prime minister, it has all come to a premature end within just 14 months of government.

It also has devastating implications for Sir Keir Starmer. There is a long list of unanswered questions.

When will a deputy leadership election take place? And who will stand? Will a candidate who wants to force the government into a more left-wing position make it on the ballot?

Or, as some believe the Labour rulebook permits, could the cabinet designate an interim deputy leader from among their number who would, in time, be anointed permanently?

Would Sir Keir commit to appointing a new deputy leader to the position of deputy prime minister as well? Would the new incumbent want that, or would they rather establish a new powerbase on the backbenches?

Could the prime minister even revisit Jeremy Corbyn’s attempt to abolish the deputy leadership? That was mooted to me by one insider this morning. They acknowledged it would be a terrible look but perhaps a least terrible option.

Who will be the new housing secretary? They will be responsible for delivering the government’s policy on housebuilding, one of its most ambitious and important commitments.

Will the prime minister use this as an opportunity to carry out a much wider shake-up of his cabinet and ministerial team, or will he want to minimise the political drama?

We’ll begin to find out the answers to some of these questions over the coming hours and days.

Other questions, such as the impact of Rayner’s resignation on the government’s popularity, will take longer to answer.

It is safe to say that this is not how “phase two” of Sir Keir’s government was meant to begin.