DUP tests are OK if they in effect mean getting rid of protocol

The party has said the new arrangements must fulfil Article 6 of the Act of Union (that part of the foundational UK legislation which guarantees unfettered trade within the nation).

Other tests include avoiding the diversion of trade (as is clearly happening, with soaring north-south movements) and that there will be no border in the Irish Sea.

The consent principle of the Belfast Agreement must be preserved and there must be no “new regulatory borders” between Northern Ireland and Great Britain.

All of this should mean, in effect, that the protocol is scrapped.

But the problem is that it might be, depending on the DUP approach to its own tests in the coming weeks, interpreted by London and Brussels as meaning that the DUP will accept modifications to the protocol.

That would mean, in effect, the largest unionist party accepting the disastrous constitutional implications of the protocol so long as they are effectively invisible.

For example, the DUP is entirely right to call for no checks going in either way between Northern Ireland and Great Britain. But it is possible that the EU and UK are close to a deal where they can claim that this has been largely met, yet the huge legislative change of the protocol remains largely in place.

The DUP is certainly in a difficult place. It is already at risk of being blamed for the collapse of Stormont because Sinn Fein has made any change in the first minister dependent on a date for the implementation of Irish language legislation, an outrageous latest example of republican blackmail.

But the scale of the protocol’s constitutional damage has become clear and unionist parties cannot credibly accept that, even if the acceptance is oblique.