Divisions over immigration have surfaced within Labour ahead of a crunch meeting this weekend to finalise the party’s general election manifesto.

Unite union boss Len McCluskey infuriated activists by declaring that the policy to “maintain and extend” free movement for EU citizens agreed at Labour’s annual conference was not “sensible” and should not be adopted at the crucial clause V meeting on Saturday.

It now looks highly likely that the free-movement proposal will be watered down, with the party promising some sort of restriction, possibly through work visas.

But Labour’s employment rights spokeswoman Laura Pidcock insisted that the issue of migrant numbers was a “false flag” and that the key focus for the party should be regulation of employers to prevent exploitation of foreign and homegrown staff.

Tories claimed that a Labour government would mean a “surge” in immigration.

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But security minister Brandon Lewis admitted that the Conservatives themselves would not be setting an immigration target, having “let people down” by failing to meet previous commitments.

David Cameron and Theresa May’s goal of reducing net immigration below 100,000 a year was never met and has now been abandoned. Home secretary Priti Patel last night said Tories would “reduce immigration overall” through the introduction of a points-based system, but Mr Lewis said that setting a specific figure would be “arbitrary”.

Ms Pidcock refused to say whether she would be happy to see immigration rise under a Labour government, insisted that targets for numbers were arbitrary.

“What we are certainly not going to do is put the lives of people on the line here in a general election campaign,” she told BBC Radio 4’s Today programme.

“We know actually that migrant labour does not undercut wages, it is exploitative bosses that seek to undermine national agreements – that’s our emphasis.”

When pushed on Mr McCluskey’s position that “it’s wrong to have any greater free movement of labour unless you get stricter market regulation”, Ms Pidcock said: “It isn’t right that we place the blame on numbers of immigrants for wages. Actually those employers that seek to undermine those national agreements are to blame for the exploitation.

“The issue is not about migrant labour, the issue is about what kind of legislative environment we have for workers, and we will create one where all workers are protected.”

Labour’s Laura Pidcock said the issue of migrant numbers was a ‘false flag’ (Getty) (Getty Images)

Mr McCluskey told The Guardian that the only beneficiaries from completely free movement of workers were “unscrupulous bosses”.

Looking ahead to this weekend’s meeting, he said: “We will have to see what’s in the manifesto, but I don’t think [the conference policy] is a sensible approach and I will be expressing that view.”

While the Tories have been committed to the introduction of an Australian-style points-based system since Boris Johnson became prime minister in July, ministers have refused to say whether that would mean cutting immigration levels.

However, in a Conservative Party press statement attacking Labour’s immigration plans, Ms Patel committed them to bringing the numbers down once Britain has left the EU, while remaining “open and flexible” to admitting high-skill migrants like scientists and doctors.

Mr Lewis told Today: “We are not setting some arbitrary target.