LABOUR is poised today to announce it will campaign for Remain in a second referendum on a Tory Brexit deal or if there is a no-deal outcome after trade union leaders agreed a shift in policy.

However, in the unions’ agreed approach, Labour could still campaign for Brexit if it won a general election and negotiated a good deal with Brussels.

But a lack of clarity still exists as the union decision noted that Labour’s campaign position under such a scenario “should depend on the deal negotiated”. This means theoretically that Labour could campaign against its own negotiated deal.

Nonetheless, one senior Shadow Cabinet source described it as a “big victory” for Remain campaigners.

The agreed line among trade unions, which included Unite, Unison and the GMB, is now likely to push the Shadow Cabinet to adopt the position when it meets on Tuesday.

Tom Watson, the deputy leader, tweeted: “Remain is who we are. Our values are Remain, our hearts are Remain. Today is a step in the right direction but our members and supporters are clear that any kind of Brexit gives us less than we have now and Labour should not support it.”

But Tom Brake for the Liberal Democrats claimed Labour was heading towards “another Brexit fudge”.

He said the unions had moved to support his party’s policy to stop a Tory Brexit but a Labour Brexit would be no better. “Labour must rule out their Brexit-supporting leader negotiating their own Brexit deal,” Mr Brake added.