Jim Allister has said that unionists must focus on opposition to the protocol and not be distracted by "fancy talk" about a tunnel to Britain.
The TUV leader was speaking amidst widespread cynicism to Boris Johnson's proposal to build a fixed link from Northern Ireland to Scotland. A 25-mile undersea tunnel has replaced his previous idea of a bridge connecting the two regions.
Mr Allister said: "No one who understands the ruinous constitutional consequences of the protocol will be distracted by fancy talk about a tunnel to Great Britain. Nor, should any be deceived again by the promises of Boris Johnson. Welcome as such infrastructure would be - if ever delivered - it would do nothing to dissipate the iniquitous protocol.
"Its border posts would merely have a new entry point, but we would still be in a foreign single market for goods, under a foreign customs code and VAT regime, all governed by foreign laws we did not make and cannot change, the undemocratic oppression of which would be overseen by a foreign court."
Mr Allister added: "Such insidious transfer of sovereignty and constitutional change can not be undone either by a tunnel or mere mitigations and easements.
"The protocol must go in all its parts.
"It cannot be made acceptable, nor should it be implemented by anyone who professes belief in the Union." Under the terms of the protocol, Northern Ireland remains in the EU single market for goods.
Northern Ireland also applies EU customs rules at its ports, even though the region is still part of the UK customs territory.
The creation of a de facto sea border with Great Britain has angered unionists.
Yesterday the European Commission vice-president said efforts to address problems with the Northern Ireland Protocol should be a two-way street.
Maros Sefcovic said the EU is "always ready to deliver" on its commitments surrounding the post-Brexit arrangements to avoid a hard border on the island of Ireland.
DUP East Londonderry MP Gregory Campbell reiterated the need for the Government to take direct and meaningful action to "restore" Northern Ireland's place in the UK internal market following disruption of supplies.
Mr Sefcovic said the EU is "always ready to deliver" on its commitments but the UK must realise the effort is a "two-way street".
"I believe if the UK used all the flexibilities which we already agreed upon in December, then also the implementation of the protocol would be much easier."
Mr Sefcovic apologised for the EU's recent attempt to trigger Article 16 of the protocol to prevent the flow of vaccines into Northern Ireland.
The move led to Unionist calls for Westminster to now invoke the so-called handbrake clause.