TUV leader Jim Allister has described the Northern Ireland Protocol as a "perilous" threat to the Union and called on the DUP and UUP to take immediate action to disrupt it.
He described the protocol as "evil genuis" and outlined proposals including ending north/south cooperation and vetoing the adoption of laws in the Assembly on the protocol.
He also said DUP Agriculture Minister Edwin Poots should stop his officials working on Irish Sea border checks.
“Together these actions would bring matters to a head and demonstrate that unionists will not be willing participants in the destruction of the Union," he said.
The Northern Ireland Protocol allows the free movement of goods between Northern Ireland and the Republic but introduced the need for customs checks between Great Britain and Northern Ireland.
In days after the EU and UK severed ties at the start of the year, supermarkets have struggled to fill shelves and retailers forced to restrict deliveries to Northern Ireland.
The North Antrim MLA criticised the 'cosy' relationship that existed between other unionist politicians and Prime Minister, Boris Johnston.
He challenged the DUP and the UUP to stop all co-operation and participation in North/South bodies.
Speaking on the BBC Radio Ulster Nolan Show, Mr Allister said: "It wasn't me that lauded the present British Prime Minister as a friend of the Union and drank champagne with him or anything else.
"That might have been the mistakes of others. Unionism was done over and not for the first time by the Conservative Prime Minister.
"All that is tragic. I believe a calculated decision was made that unionism was an easier push over than nationalism and therefore let's go for the soft touch."
He said his proposals would not necessarily solve the issues.
"A suite of actions is required," he said, "but it would be a start and signify a resolution to stand up for what matters most of all - the Union.
"It would also dispel a perception that those unionists in power care more for their positions than they do for the principles at stake.
“Across the unionist community there is a significant loss of morale which requires evidence of a ‘fight back’. We cannot go on as we are, as if nothing has happened.
“I, therefore, appeal to the DUP and UUP to act, before it is too late.”