The Labour Party is haemorrhaging members amid a growing backlash over Jeremy Corbyn’s stance on Brexit, according to party insiders.

At the height of Corbyn’s popularity following the general election in 2017, Labour was considered the “largest party in western Europe” with more than 500,000 members.

In recent months, however, it has lost up to 150,000 members, according to three sources within the party. It is estimated that up to 100,000 are not up to date with their subs and enrolment has slumped to around 385,000.

A Labour insider said the downswing had already cost around £6m. “The party is skint,” the source said. “There have already been some recriminations about the amount spent on last summer’s botched music festival Labour Live.

“Although there is