F or weeks, Andy Burnham’s supporters had told MPs to “hold the line”, that he had a seat in parliament in his sights and that he would be a contender in any leadership contest. That was never the full truth. His path to No 10 – if he makes it – is littered with more failed attempts than almost any other politician. Two leadership contests, a block on a return in Gorton and Denton, and quite a few aggrieved MPs in the north west who have had to spend weeks batting off suggestions they will give their seats up for him. By Thursday this week, with almost all the likely contenders ruling themselves out, Burnham’s backers in parliament were getting desperate. Only the tiniest handful of the Greater Manchester mayor’s closest advisers knew the truth: there was finally a seat coming which no one expected. When Wes Streeting announced at 1pm on Thursday that he was resigning from Keir Starmer’s cabinet , it set off a bombshell ; outwardly, things did not look hopeful.…