Labour has been accused of being anti-unionist after the party’s shadow Northern Ireland secretary said it would not campaign for keeping the UK whole.

Louise Haigh said that if the party were in government, it would stay neutral in a referendum on keeping Northern Ireland part of the UK.

Ms Haigh told GB News: “It’s not my job to be a persuader for the Union. One of the important principles was that Britain should not have any strategic or selfish economic interest in the constitutional status of Northern Ireland.

“It’s up to the people of Northern Ireland to determine their own constitutional future.”

Ms Haigh said that while Labour was a unionist party, “if there is a border poll we should remain neutral – I think that is an important principle”.

‘Conservatives will never be neutral on Union’

Brandon Lewis, the Northern Ireland Secretary, tweeted: “‘Stronger Together’ clearly doesn’t apply to Labour’s position on Northern Ireland.”

Mr Lewis called on Sir Keir Starmer to “have a word with his shadow Northern Ireland Secretary” after the Labour leader said earlier this year he would make the case for Northern Ireland to remain part of the United Kingdom.

The Northern Ireland Secretary said the Conservatives “will never be neutral on a Union”.

Meanwhile, a Tory source accused Labour of never having resolved its “unionist identity crisis”. The source said: “With the Social Democratic and Labour Party as their sister party, and their shadow Northern Ireland secretary emphatically saying it is not her role to be a ‘persuader for the Union’, how they can claim to be a unionist party with a straight face is beyond belief”.

A Northern Ireland spokesman said: “The principle of consent enshrined in the Good Friday Agreement means that it is for the people of Northern Ireland to decide on its future constitutional status.

“There is no stipulation within the Good Friday Agreement that the UK Government must remain neutral in any border poll campaign.”