A byelection win is a fillip for Andy Burnham and shows Zack Polanski must confront the failures damaging his party’s credibility and appeal By holding Holborn and St Pancras, Andy Burnham’s Labour has shown it can attract liberal and left-leaning voters. The seat has substantial numbers of young adults, students, professionals and Muslims – offering fertile ground for the Greens’ ecopopulism.

However, Labour prevailed. Having won leave-voting Makerfield in June, Mr Burnham can now claim an appeal that bridges Labour’s divided electorate. It’s worth noting that turnout in London was low and Labour’s vote share fell 3.7 points. But that compares with an average 19.3-point fall in four byelections under Mr Burnham’s predecessor. The new leader clearly has bought Labour breathing space and checked the Green advance.

The Greens more than tripled their vote share in the constituency to 33%. But they were beaten. Labour’s Sagal Abdi-Wali took 45% in Sir Keir Starmer’s former seat, leaving Zack Polanski’s ambition of entering parliament unfulfilled. For a party that began the year promising to turn voters’ hunger for change into a serious challenge to Labour, this was a sobering moment. The passing of a motion declaring “Zionism is racism” at its conference probably cost the party support – though the result in central London alone cannot definitively say that.

There is a separate question of leadership. Mr Polanski now says he would have voted against the motion. Why, then, did he not make his opposition clear when it mattered last weekend?