The Guardian can also reveal that Burnham is backing a new political network called Mainstream, which is drawn largely from the soft left and aims to influence the direction of the party.
Steered by the thinktank Compass, it is planning to mobilise a grassroots motion at party conference demanding the
abolition of the two-child benefit cap, as well as aiming to campaign in constituency Labour parties and across the country for what they describe as bold but practical reforms.
Burnham said he was concerned about the balance of the cabinet after the reshuffle and the deputy leadership contest was a moment to try to shift the party away from being London-centric. One of his preferred candidates, Haigh,
who resigned last year over a scandal about a conviction for fraud over a missing mobile phone, is understood not to have made up her mind whether to run.