Mr Watson is now at loggerheads with most of the Shadow Cabinet. "Our priority is for a general election".
No one can trust Johnson's word on Brexit.
Mr Watson claimed a public vote on Brexit was the only way to break the deadlock gripping Parliament as an election might fail to solve the "chaos".
Prime Minister Boris Johnson
"I want to lead a Labour government that will bring people together, and a relationship with Europe, either in the European Union or an effective trading relationship with Europe, in which we have a dynamic relationship on regulations and rights so we don't become a Donald Trump island, on the edge of Europe, undermining the social advances that have been made". Labour's manifesto will promise a referendum on Brexit, with a choice between Remain and a renegotiated Withdrawal Agreement.
He will also argue that if a referendum were to follow an election, then Labour should commit "unambiguously and unequivocally" to campaign for Remain. He may have to give MPs the freedom to choose their side or risk opening up even worse divides.
Labour is "united around the idea there should be a referendum" on the outcome of Brexit, the party's shadow Brexit secretary Sir Keir Starmer has said.
Labour's increasing shift towards Remain has angered MPs in some Eurosceptic constituencies who fear the stance could alienate voters.