The left-wing party is split over how hard to challenge Andy Burnham, with some urging against a ‘full campaign’ against the electoral reform believer

Former party leaders and councillors warned the contest must be approached with 'trepidation' - as Andy Burnham's appointment could offer a 'unique opportunity'.

Party politicians and activists including a former leader have told Zack Polanski that it is in the party's interests to lend support to the Greater Manchester mayor on June 18.