Chris Mason: Questions multiply for the man tipped to replace Starmer

So what is driving Burnham's current magnetism? In short, he is seen as a winner and Sir Keir is seen as a loser. And not just any winner – a winner against Reform UK, in a part of the country where Reform did very well in the English local elections last month. Without question, Burnham didn't choose an easy seat to contest to return to Parliament. But it is also true to say that he is very popular in Greater Manchester and his popularity remains largely untested beyond. "It feels like lots of Labour MPs are dashing for a train that's about to leave the station, but they haven't any idea where it's going," is how one figure put it to me, suggesting there is still plenty the party and the country doesn't yet know about Burnham's prospectus for government. He set out some ideas, in broad terms, during the by-election campaign, but – perhaps understandably – wanted to focus then on the local concerns that might help ensure he won the seat. In a social media post reflecting on the prime minister's decision to stand down , he added that "people want to see progress on economic growth, cost of living, public services, housing and opportunities for the next generation". Few, of any political persuasion, would disagree with this. How he would deliver it will now face intense scrutiny. It is the lack of detail and potentially very narrow window to fill in the blanks that are causing jitters for some in the party. …