Britain is in crisis yet again, and this time post Brexit. Two former Prime Ministers, pre-eminently Tony Blair (Labour) and Sir John Major (Conservative), have urged MPs to reject what they call “shameful attempts” to override parts of the Brexit Withdrawal Agreement.

The two have accused their government of “embarrassing” the UK by seeking the power to change the details of a treaty agreed last year with the EU. Happily for Prime Minister Boris Johnson, the crisis may have blown over for now with his controversial bill having cleared its first parliamentary hurdle by winning the first House of Commons vote by 340 to 263 votes.

The Internal Market Bill has been opposed by the Opposition and senior members of the ruling Conservative party who are determined to revolt against the legislation as it progresses through further stages in its parliamentary process. And this could happen despite Mr Johnson’s 80-seat majority in the Commons.

Having effected the messy divorce, the Prime Minister is rather unlikely to be overly optimistic over the nitty-gritty quite yet. It cannot be said that he has won the first round. While Whitehall contends that the bill has vital safeguards to protect Northern Ireland and the rest of the UK, its critics have warned that the legislation runs the risk of damaging international law.

A senior minister was not off the mark when he claimed that the United Kingdom faces an “unprecedented situation”. Justice Secretary Robert Buckland said the powers being sought by ministers to amend aspects of the Northern Ireland Protocol were an “insurance policy” to be used only if attempts to settle differences in other ways failed.

The Protocol, a key part of the Withdrawal Agreement, signed by both sides last year, is designed to prevent a hard border returning to the island of Ireland. Should the bill become law, it will empower ministers to modify or “disapply” rules relating to the movement of goods between Britain and Northern Ireland that will come into force from 1 January if the UK and EU are unable to strike a trade deal.

The discord has been stoked by an article in The Sunday Times by Sir John and Mr Blair ~ former Conservative and Labour prime ministers respectively. In an exceptional conjunction of two rival party leaders, they argued that the government’s actions were “irresponsible, wrong in principle and dangerous in practice”.

Strong words indeed for the incumbent Tory head of government. “It raises questions that go far beyond the impact on Ireland, the peace process and negotiations for a trade deal ~ crucial though they are. It questions the very integrity of our nation,” they said. The former PMs, both vehement opponents of Brexit, said that respecting treaty obligations was “just as important” as domestic law, and called on MPs to reject the legislation.

“As the world looks on aghast at the UK ~ the word of which was once accepted as inviolable ~ this government’s action is shaming itself and embarrassing our nation.” Leaders have raised pertinent issues; the bill calls for reflection.