The Green Party has suffered two council by-election defeats in a blow to Zack Polanski. The Greens were pushed into third place in the Wreake Valley ward on Charnwood Borough Council in Leicestershire, with the Tories winning and Nigel Farage’s Reform UK coming second.

The Greens also lost the Walkley seat on Sheffield Council, which was won by Labour. It comes ahead of a crunch parliamentary by-election in Sir Keir Starmer’s Holborn and St Pancras constituency, where Mr Polanski is standing.

Pollster Luke Tryl said the Greens are at risk of losing voters to both Labour and the Conservatives.

The Left-wing party surged in the polls after Mr Polanski became leader last year, but it has dropped in recent months as Labour enjoys a bounce under Andy Burnham.

Mr Tryl, UK director of More in Common, said: “Two by-election losses show risk Greens end up in a pincer movement of their own if momentum stalls as Burnham regains disillusioned progressives who went to the Greens from Labour. But at the same time, having less appeal to voters in rural areas, losing to the Tories.”

It comes ahead of the Holborn and St Pancras by-election next month, which was triggered by the resignation of Sir Keir as an MP after he was replaced in No 10 by Mr Burnham in July.

The ballot is seen as a two-horse race between Labour leader of Camden Council Sagal Abdi-Wali and Mr Polanski.

The latest national YouGov poll puts Labour and Reform neck and neck in first place, both with 23%.

The YouGov survey puts the Tories in third place with 20%, while the Lib Dems are on 13%, the Greens 11%, and Rupert Lowe’s Restore Britain on 3%.