UPDATE 1-UK Labour's must back 'public vote' on Brexit after EU vote -McDonnell

Britain's main opposition Labour Party must back a public vote on Brexit, Labour's finance chief John McDonnell said on Monday after voters deserted the party in droves in European elections amid anger over the country's delayed departure from the EU.

A Labour source said McDonnell was using the term "public vote" to cover both Labour's preference for a national election or a referendum. "Can't hide from hit we took last night. Bringing people together when there's such a divide was never going to be easy," McDonnell said on Twitter.

"Now we face the prospect of Brexiteer extremist as Tory (Conservative) leader and the threat of no deal, we must unite our party and country by taking the issue back to people in a public vote."