Dan, Treaties the UK has agreed are binding on us in international law but not made effective in domestic law save where specifically provided for in an Act of Parliament (eg EC Act 1972 made effective in UK law UK's treaty obligation to give primacy to EU law). https://twitter.com/KeohaneDan/status/1319708744310267907

So Parlt can override/renege on/set aside UK's Treaty commitments and revoke any domestic law remedy for that breach even though the obligationremains binding in international law. Unilateral action by Parliament cannot remove the international legal obligation itself.

UK would have to deal with the political, reputation, diplomatic consequences & any retaliatory action justified by the treaty.

Principle established by UK courts in Factortame 2 case (1989) is relevant. Judges ruled that EU Act 1972 meant that a court could and would disapply an Act of Parliament if it conflicted with EU law.

But also were clear that if a future Act expressly set aside those ECA obligations (eg repeal or a "notwithstanding" clause), the courts would uphold that Act even though UK would have breached treaty obligations.

In sum, Parlt has power to revoke any domestic legal obligation to implement a treaty but not the international legal obligation itself. Whether it would be right or wise to do so is an entirely different question & for which there are only political not legal answers.