Rebecca Long Bailey’s campaign has fractured at an early stage in the Labour leadership race as at least two of her advisers quit over the strategy being spearheaded by Jon Lansman, her campaign strategist.

Ms Long Bailey, the leading left-wing candidate to succeed Jeremy Corbyn, is thought to have recruited a number of advisers from her own staff and the offices of Mr Corbyn and John McDonnell, only for them to clash disastrously with Mr Lansman as he attempted to get her to adopt a softer left position.

Mr Lansman is a veteran socialist activist who played leading roles in Mr Corbyn’s two leadership campaigns and founded the Momentum group.

The officials known to have walked out over disagreements with him