Angela Rayner has just resigned as Deputy Prime Minister, although I can't see from the initial reporting whether she has also resigned as Deputy Leader of the Labour Party (an elected rather than appointed position, of course). The latter point could be crucial in terms of her long-term political future, although if a vacancy for the leadership were to come up in the next few months, her goose would still be pretty cooked.
Understandably, punters think her chances of replacing Starmer have just fallen off a cliff. She had been favourite for a time, but these are the latest odds -
Wes Streeting 6.8
Andy Burnham 8.4
Yvette Cooper 15
Darren Jones 19.5
Angela Rayner 22
Bridget Phillipson 25
Rachel Reeves 30
Ed Miliband 34
Some people will assume that Wes Streeting's chances have strengthened dramatically, but you have to look at this from the point of view of those who will ultimately make the decision - ie. Labour party members. In this particular scenario, they are not likely to conclude that the problem is that the current leadership is not sufficiently right-wing, because Starmer has pushed the party as far to the right as it has ever been (including in the Blair years). They are much more likely to be looking for a soft left corrective, and if Rayner can no longer provide that, they'll try to seek out an alternative champion. Andy Burnham is the person who would most obviously fit the bill - but just one snag, he's not actually eligible because he's not an MP. That can theoretically be overcome but not easily.
So I think the person whose chances have just improved dramatically is Ed Miliband. That may not be showing up in the odds yet, but I think the logic for it is sound.