Sinn Féin leader Mary Lou McDonald said this morning: "Today, Andy Burnham becomes the seventh British Prime Minister in a decade. His time in office will be important as it coincides with the 30th anniversary of the Good Friday Agreement and advancing towards referendums on Irish Unity. I hope his government approaches this work with the courage and imagination shown by previous Labour governments during the peace process."

Ms McDonald said: "When Labour assumed office after the last Westminster election, I stated Sinn Féin's intention to work constructively with the incoming British Government to address the considerable challenges and opportunities before us. That remains our position.

"The appointment of Andy Burnham as Labour Leader and British Prime Minister offers an opportunity to begin a new chapter in relations between Britain and Ireland. I hope his government approaches that task with the courage and imagination shown by previous Labour governments during the peace process.

"As we approach the 30th anniversary of the Good Friday Agreement, peace is secure. The future political direction of Ireland, and our relationship with Britain, must continue to be shaped by the full implementation of the Good Friday Agreement.

"That work remains unfinished. Outstanding commitments must now be honoured in full, including provision for a referendum on Irish reunification in accordance with the Agreement. "The conversation on Irish unity has moved decisively into the political mainstream. It is taking place in the Dáil, across civic society, universities, businesses, trade unions and communities throughout the island. The direction of travel is clear. Ireland is moving towards a referendum on unity. The outcome will belong to the people alone, but governments cannot postpone preparation until a referendum has been called. Preparation must begin now.

"Sinn Féin has brought forward proposals to reform the Assembly in the immediate term by removing outdated vetoes, improving its functioning and operation and, above all, strengthening its capacity to deliver for workers, families and communities. The Executive also continues to be hampered by an insufficient block grant from Westminster. An Executive budget is an immediate priority.

"Sinn Féin will judge Prime Minister Burnham by his actions. As we approach the 30th anniversary of the Good Friday Agreement, we will assess his government's commitment to investing in public services, providing the Executive with the resources and powers it needs to deliver, and full implementation of the Agreement. We will make it clear that the British Government's approach to legacy at this time is not acceptable and will be resisted by victims and survivors with the full support of Sinn Féin, and it must change.

"The opportunity now exists to build on the progress of the past three decades. That will require political leadership, respect for the Agreement in all of its parts, and a shared commitment to shaping a future based on democratic choice and genuine partnership between the people of Ireland and Britain."