Mr Donaldson will be appearing before the House of Lords Constitution Committee to discuss the current state of the Union, the Northern Ireland Protocol, intergovernmental relations and constitutional reform.
The session, which is part of the committee’s inquiry into the future governance of the UK, will see Mr Donaldson quizzed on questions such as, how he would describe the current state of the Union? What impact has the NI Protocol had on Northern Ireland’s constitutional status? And in what circumstances he thinks it is acceptable for the UK Government to legislate in devolved areas?
His appearance comes amid major pressures for the party, with several polls claiming much support has moved to other unionist parties.
Last week Mr Donaldson said that if the UK government has not addressed the threat of the protocol to NI’s constitutional position by the end of the month, he will withdraw his ministers from the Executive - something he is expected to spell out once again tomorrow in stark terms.
He is also expected to say: “The Northern Ireland Protocol threatens to provoke the most serious constitutional crisis in Northern Ireland’s hundred years of existence.
“The protocol, in its present form, not only creates a border down the middle of the United Kingdom but it also threatens the economic integrity of the UK and has already undermined the sixth Article of the Act of Union.
“While I welcome the Government’s command paper on the protocol, it is essential that if agreement cannot be reached in the short term with the EU, that the government is prepared to take unilateral action as provided for in the protocol itself. This is the best way to ensure the stability that will enable us to build stronger governance arrangements for Northern Ireland within the context of the Union.”
He is expected to tell peers that it is “simply not acceptable” that NI consumers and businesses are treated like “second class citizens in their own country”.
“No unionist should be asked to implement arrangements that are undermining the economic integrity of the U.K. If the choice is between remaining in office or implementing the Protocol in its present form, then the only option for any unionist Minister would be to cease to hold such office.
“The Protocol does not represent the best of both worlds but rather it endangers the Belfast Agreement and the peace and stability that has been achieved in recent years. As I made clear last week what is needed are significant and substantial changes which satisfy the tests I set out in Parliament in July and remove this unnecessary Irish Sea border that is disrupting trade between GB and NI and undermining the constitutional integrity of the UK.”