A new UK government after the general election must bring a “step change” in how Northern Ireland is funded, Sinn Féin’s leader has said.

Mary Lou McDonald was speaking at the launch of the Irish republican party’s manifesto for the UK general election on 4 July.

It includes pledges to deliver flagship Stormont executive projects and continue pressing the UK government to set a date for a referendum on Irish unity.

Ms McDonald said that “Tory austerity” has hit Northern Ireland “so badly” and it continues to be underfunded by the UK Treasury.

She said Northern Ireland being separated from the Republic of Ireland, known as partition, is “bad for your health”.

“Partition has been bad for the economic prospects of this part of Ireland,” she said.

Speaking in Belfast, Ms McDonald added: “Our big task in our opinion, and this is a collective responsibility right across the political system here, is to confront Tory austerity and any potential for an ongoing austerity agenda coming from London.

“There will be a change of government across the water and with that change of government has to come a step change in how the north is funded.”

Sinn Féin is standing candidates in 14 of the 18 constituencies in Northern Ireland.

It is not contesting Belfast East, Belfast South and Mid Down, Lagan Valley and North Down.

The party has instead encouraged voters in these constituencies to support “progressive parties who will reject Tory cuts”.

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Sinn Féin MPs do not take their seats in the House of Commons because of the party’s policy of abstentionism.

Ms McDonald defended the policy, saying that Sinn Féin MPs work “incredibly hard”.

Sinn Féin is also the main opposition party in the Republic of Ireland.

In local and European elections there earlier this month, the party made some small gains but fared worse than many opinion polls had predicted.

The Sinn Féin leader said there was “no room for being despondent” about the results and she is confident the party will “perform very strongly” in the Westminster election.

She joked that Sinn Féin being an all-island party meant “we’re kind of like the GAA (Gaelic Athletic Association), only better – or the IRFU (Irish Rugby Football Union)”.

In the last Westminster election in 2019, Sinn Féin secured seven MP seats – one fewer than the Democratic Unionist Party (DUP).

The Social Democratic and Labour Party (SDLP) won two Westminster seats, while the Alliance Party secured one.

Sinn Féin overtook the DUP to become the largest party at Stormont for the first time in assembly elections in 2022, and repeated the feat at council level in 2023.