Labour is set to commit to giving full voting rights to foreign nationals living in the UK in a move that could have a seismic impact on a future Brexit referendum.

A motion expected to be approved by the party's annual conference on Monday promises that a Labour government would “extend equal rights to vote to all UK residents. If passed, the text would become official party policy.

The change would extend the right to vote in general elections to anyone with residency rights in the UK, regardless of their nationality. Currently only British, Irish and Commonwealth citizens are allowed to vote in general elections. Other foreign nationals living in Britain can vote only in local elections and European elections.

The proposal will be debated at the Labour conference in Brighton after being quietly included in a motion that says a Labour government should "maintain and extend" freedom of movement even if Britain leaves the EU, including by opposing any new immigration system based on migrants' income or skills.

The text says that, if Labour wins the next election, it will "extend equal rights to vote to all UK residents".

It also says that a Labour government would "close all detention centres" and "scrap all Hostile Environment measures", including restrictions on migrants' access to the NHS and welfare payments.

Extending the voting franchise would likely have a major impact if it was implemented before any second Brexit referendum and applied to the subsequent poll, with the 3 million EU citizens living in the UK easily enough to swing any vote heavily towards Remain. In the 2016 referendum, only people with the right to vote in UK general elections were allowed to vote.

It would also be likely to deliver millions more votes for pro-EU and pro-immigration parties in future general elections.

The move has been co-ordinated by the Labour Campaign for Free Movement and is expected to be approved by conference delegates when it is put to a vote on Monday.

A statement accompanying the motion, signed by Labour MPs, trade unionists and representatives of EU citizens in the UK, said it was "fundamentally wrong" that millions of people living in the UK are currently denied the right to vote.

Brexit and climate protests at Labour party conference: In pictures Show all 12 1 /12 Brexit and climate protests at Labour party conference: In pictures Brexit and climate protests at Labour party conference: In pictures Labour leader Jeremy Corbyn walks past anti-Brexit campaigner on the second day of the party conference in Brighton AFP/Getty Brexit and climate protests at Labour party conference: In pictures A protester holds a sign mocking Labour leader Jeremy Corbyn's Brexit stance at the party conference in Brighton EPA Brexit and climate protests at Labour party conference: In pictures Activists from anti-climate change movement Extinction Rebellion march on the Labour conference in Brighton AFP/Getty Brexit and climate protests at Labour party conference: In pictures Delegates take part in an informal vote on Labour's Brexitr stance at the party conference in Brighton AFP/Getty Brexit and climate protests at Labour party conference: In pictures Shadow foreign secretary Emily Thornberry leads a march in support of a second referendum on Brexit Getty Brexit and climate protests at Labour party conference: In pictures Anti-Brexit protesters take part in a People's Vote rally during the Labour party conference in Brighton EPA Brexit and climate protests at Labour party conference: In pictures Extinction RebelliActivists from anti-climate change movement Extinction Rebellion march on the Labour conference in Brightonon EPA Brexit and climate protests at Labour party conference: In pictures Extinction Rebellion activists march on the Labour conference in Brighton AFP/Getty Brexit and climate protests at Labour party conference: In pictures A delegate arrives carrying a briefing from the Labour Representation Committee to the Labour party conference in Brighton Getty Brexit and climate protests at Labour party conference: In pictures Prominent anti-Brexit campaigner Steve Bray protests on Brighton beach during the Labour party conference Reuters Brexit and climate protests at Labour party conference: In pictures Anti-Brexit protesters take part in a People's Vote rally during the Labour party conference in Brighton EPA Brexit and climate protests at Labour party conference: In pictures Activists raise a banner calling for the Labour party to restore the original Clause 4 of its constitution, which would pledge the party to nationalising all industry Getty

It said: "Labour must be the champion of migrants’ rights in British politics. We must not allow working class people to be divided on the basis of where they are from.

"But speaking out on behalf of migrants is not enough. As representatives and activists of the labour movement, we understand that people only ever win justice and beat prejudice when they have a voice of their own. At minimum, this means having the right to vote."

It added: “Millions of people who have made their home here cannot vote here. It is fundamentally wrong that so many millions of people are denied a vote in decisions which affect them deeply.