A motion to “stop Tory Brexit and win a radical Labour government” will be put forward by the unprecedented number of Constituency Labour Parties (CLPs).
Supporters want to see Labour vote down Theresa May’s Brexit deal in October, call a general election, then call another referendum, or People’s Vote.
The surge in support for a People’s Vote from activists is backed by key figures, including Manuel Cortes, general secretary of the TSSA union which supports Jeremy Corbyn.
Mr Cortes said Brexit backers had tried to “pin the blame” for falling living standards on migrants when “their austerity” was the cause.
“Brexit is a Tory con trick for the benefit of the richest 1 per cent,” he said. “It will rob workers and drive down wages.
Ann Pettifor, an economist who advises shadow chancellor John McDonnell, said she was “no fan of the EU elite” or “neo-liberal orthodoxy”, but warned Brexit would “bolster the far-Right”.
She said: “Brexit isn’t just about Britain’s membership of the EU.
The call comes after a series of town hall meetings as part of the Left Against Brexit tour of Manchester, London, Liverpool, Bristol, Nottingham and Birmingham. The tour, run by Another Europe Is Possible, will continue in late August and September with events in Glasgow.