Green Party leader Zack Polanski has said he'll stand in the by-election triggered when former Labour Party leader Sir Keir Starmer announced he would be stepping down as MP for the seat of Holborn and St Pancras in north London. Labour has said that it will close nominations for its potential candidates by noon on Friday. At the last election Sir Keir had a majority of over 11,500. #ZackPolanski #KeirStarmer #ByElection #LabourParty #C4News