Zack Polanski has been formally confirmed as the Green Party's candidate for the Holborn and St Pancras by-election, winning an online members' vote on Thursday night against local councillor Hamza Chowdhury. New details have emerged since his selection was first reported, including the identity of Labour's candidate, Camden Council leader Sagal Abdi-Wali, and a row over racist remarks made about her by Reform UK's Zia Yusuf, which Polanski condemned as "despicable" while pledging solidarity with her. The by-election, called after Sir Keir Starmer quit as an MP following his removal as prime minister by Andy Burnham, is seen as an early test of public opinion under the new Labour leadership.

Labour has held the seat since its creation in 1983, with only two MPs, Frank Dobson and Starmer, but the Greens have gained ground locally, growing from one to ten councillors in Camden after May's local elections. Polanski, London Assembly member and Green Party leader, framed the race as a straight fight between Labour and the Greens, noting the party's momentum despite a national polling dip since Burnham took over. The vote will be held on 8 October, with Polanski saying he intends to campaign on doorsteps throughout the 27-day run-up.