Zack Polanski to stand for Starmer's old seat as Burnham faces first by-election test

Zack Polanski, the Green Party's London Assembly member, has confirmed he will stand in the by-election for Holborn and St Pancras - the seat Keir Starmer held before becoming party leader and then giving it up when Labour lost the election.

The Guardian reports that Green Party members have backed Polanski's candidacy, while the Daily Express frames it as a major blow to Andy Burnham's new government. GB News notes Polanski has formally launched his bid. The seat, which Starmer held with a majority of over twenty thousand, becomes vacant as Starmer stands down from Parliament. Whether the local Green constituency party will formally select Polanski remains to be seen, the Daily Mail reports, though member support appears strong.

The by-election arrives barely a month into Burnham's premiership - a test not of policy but of the new government's standing when voters face an actual ballot paper. By-elections measure punishment more than policy: how many of those who voted Labour in the general election will use this one to send a message. The Greens ran second in Holborn and St Pancras at the general election, making this the obvious seat to press their advantage. For Burnham, the question is not whether Labour holds it - the majority is enormous - but by how much the majority shrinks, and whether the result reads as a vote of confidence or the first crack.

The writs will be moved in the coming weeks. The count will tell us whether the new government's honeymoon extends to actual voters, or whether it ended before the moving vans arrived at Downing Street.