In any negotiation process all participants need to be conscious of an inherent risk, namely, that their own participation creates a sense of ownership and attachment.

The long hours, the focus on one new draft after another can cloud the original objective. The desire to produce the right deal can be superseded by the perceived need to produce a deal.

This is why all negotiations need measures to prevent this, a check mechanism and preferably multiple ones. With the current UK-EU negotiations, there are two identifiable check mechanisms or lines of defence to concluding an unwise agreement – Cabinet and Parliament.

Last week, I wrote to the Prime Minister outlining broad concerns about the direction of travel.

This could be discerned from shifts in public comments, private engagements and what was being briefed in London, Dublin and Brussels. I wrote in the hope of reassurance and with the desire that an acceptable deal for us all was within grasp. Instead, I received confirmation that we were right to be concerned.

If what is outlined in the reply is the type of deal the Prime Minister intends to conclude, then the DUP could not support a deal which annexes Northern Ireland from the rest of the United Kingdom. Indeed, many others in Westminster and throughout the United Kingdom, true to their commitments to respect the referendum, the national interest and to the Union, have contacted me to voice their concern.