A founding member of the DUP has said the Northern Ireland Protocol has created a "crisis for unionism".
Wallace Thompson, an associate of Rev Ian Paisley and former special advisor to then finance minister Nigel Dodds, told The News Letter that unionists had been repeatedly betrayed over the years.
"I still believe in the union but the protocol has created a feeling of crisis for unionism once again and I feel we must learn from what has happened to us in the past," he said.
"As unionists we've been betrayed over and over again and we're always on the back foot.
"There's a pattern that's repeated - there's the betrayal, there's the fightback, there are the attempts to undo the damage that rarely ever succeed."
With the centenary of Northern Ireland being marked this year, Mr Thompson added: "We've been treated shabbily by the British establishment and my mood is probably one of reflection more than celebration."
He said he still wants Northern Ireland to remain within the union but "there needs to be a meaningful, open and honest debate".
Mr Thompson said that "too many nationalist politicians and commentators seem either unable or unwilling to understand the Ulster Protestant mindset".
"It's often portrayed by them as triumphalist and sectarian, whereas it is based on genuinely held and totally legitimate principles.
"Over the years when it has reacted angrily, it has done so out of a sense of fear that it was being threatened with destruction."
