Unionists urged to 'reach forward with a vision' following resignation of Sir Jeffrey Donaldson as DUP leader

Mr Beattie said it is important to ensure that pessimists don’t become the loudest voices during a period of inevitable “unheaval” within the largest unionist party.

“When you have that instability, that's when those negative, pessimistic, isolationist voices come to the fore and we must make sure that doesn't happen.

"Unionism is bigger than one person or one party. We need to reach forward with a vision, with policy - that is the important thing to do now, not to regress,” he told the BBC's Nolan Show.

Asked if he thought the DUP oversold the deal when they said the Irish Sea border didn't exist anymore, he said: "Yes, of course they did. It does exist. It has not gone away. The two-year boycott and the deal we ended up with did not change anything of substance whatsoever".

Also speaking on the same programme, politics professor Jon Tonge said: “In effect, Gavin Robinson is ‘continuity Donaldson’ and policy will remain unchanged. Gavin Robinson was equally enthusiastic as Jeffrey Donaldson in terms of this deal.”

Prof Tonge said there are many DUP representatives who oppose the deal, and added: “They are now a majority of the DUP’s MPs, now that Jeffrey Donaldson is no longer a DUP MP.

"They are a majority of the DUP’s members of the House of Lords, we don’t know whether they are a majority or otherwise in terms of the DUP’s MLAs but there are a significant number”.

Prof Tonge went on to say: “The DUP has got to decide, and decide quickly, what the message actually is, because there has been very mixed messages”.

In relation to the PSNI's warning to social media users - not to publish any information that would identify people who have made complaints about Sir Jeffrey Donaldson - Doug Beattie was asked if he thought the police should be "making an example" of offenders rather than issuing warnings.

"Absolutely, we should do this. Not to protect anybody other than the victims. The victims are the ones we need to be protecting here,” he said.