Grassroots Labour activists are set to clash with Jeremy Corbyn over Brexit policy in crunch votes on whether to campaign to stay in the European Union.

The Labour leader has called for a neutral position going into a general election, saying that he would negotiate a new Brexit deal with Brussels which would then be put to a referendum.

But delegates at Labour’s conference in Brighton will vote on whether the party should campaign to stay in the European Union, even if that means rejecting a deal Mr Corbyn has negotiated with the EU.

Shadow chancellor John McDonnell, who has said he will campaign for a Remain vote in the promised referendum, said the process put forward by Mr Corbyn was “logical” and insisted “there isn’t any war in the Labour Party” over the issue.

“What we’re saying is, when we know what the deal is, we’ll have a special conference and then determine our position,” he told BBC Radio 4’s Today.

“It’s very difficult for people to determine their position in advance of knowing the detail of that deal, but my view, actually I think, because I campaigned for Remain, I can’t see at the moment a better deal being achieved. And that’s my view.

“That’s why I’m saying I’m happy to go along with this logical sequence. And I’m happy for others to challenge me and say, ‘actually, no, this is a better deal’ – I’d like that debate. ”

Shadow cabinet ministers including Emily Thornberry and Tom Watson have called for the party to back a Remain vote now, rather than wait for a special conference after the election.

Their actions led to Unite union boss Len McCluskey suggesting they should either get in line or “step aside” from their shadow cabinet roles.

Mr McDonnell told Sky News: “Len is being Len. We are working together as a party to make sure the people have a choice and the people will decide.”

The result of the Brexit vote will hinge on whether the unions decide to back Mr Corbyn’s position.

Before the Brexit showdown, Mr McDonnell will deliver his keynote speech and confirm plans for Labour to fund free personal care for elderly people in England.

The pledge to fund free personal care, which would cost an estimated £6 billion a year in 2020/21, would more than double the number of people receiving state-funded support, Labour said.

In a rally on Sunday night, Mr McDonnell indicated that a pledge to reform the social security system, including scrapping Universal Credit, would be included in Labour’s first Queen’s Speech.

He said there has to be a proper social security “safety net”.

“That has to be on the basis of enabling people to have a decent quality of life with an adequate income.

“That has to mean getting rid of the bloody Universal Credit.”