Zack Polanski announces candidacy for the Holborn and St Pancras seat to be vacated by British ex-PM Keir Starmer.

Former PM says it is right time to go, which will trigger byelection that Greens’ Zack Polanski could target

Sir Keir Starmer told the Camden New Journal that he would focus on issues such as “defence, security, trade and technology".

Greens will target former prime minister’s seat in central London byelection