LONDON (AP) — The former deputy leader of Britain's Labour Party says he left politics in part because of the nasty mood inside the left-wing party, which was soundly defeated in a national election earlier this month.

Tom Watson told the Guardian newspaper in an interview published Saturday that he found the atmosphere inside the party unbearable.

"The point is that the brutality and hostility is real and it's day to day," Watson said of the Labour Party under Jeremy Corbyn's leadership.

Watson said in November that he was stepping down as deputy leader and would not seek re-election. He had been in conflict with Corbyn's supporters for months, in part because of his desire for a second referendum on whether Britain should leave the European Union.

He said Labour never had a clear message on Brexit during the election campaign, while Prime Minister Boris Johnson was able to win easily with his “Get Brexit done” refrain.

Watson said Corbyn should have resigned several years ago when he lost the confidence of Labour legislators in Parliament despite retaining the backing of the party's general membership.

“I thought, as soon as the leader loses the confidence of the parliamentary party it's almost impossible to see how you can form a government," Watson said. “I thought Jeremy should have resigned, and he nearly did."

Johnson's Conservative Party won a substantial majority in Parliament in the Dec. 12 vote, leading Corbyn to say he will resign his post when the party chooses a new leader early next year.