Boris Johnson has been hit by a devastating attack from a former loyal ally as he embarks on bruising Commons clashes on a bitterly contentious piece of Brexit legislation.
In a huge boost for rebel Tory MPs, Geoffrey Cox, the prime minister’s pro-Brexit attorney general until February this year, has condemned the move to override Mr Johnson’s Brexit deal.
“It is unconscionable that this country, justly famous for its regard for the rule of law around the world, should act in such a way,” Mr Cox wrote in a wounding attack on Mr Johnson in The Times.
Controversial Brexit legislation explained
And in what appears to be a highly personal attack on Mr Johnson, he wrote: “No British minister should solemnly undertake to observe treaty obligations with his fingers crossed behind his back.”
The legislation is under attack because it overrides parts of the EU divorce settlement negotiated by Mr Johnson, who described it as “fantastic” and “oven ready” when he did the deal.
But an attack from such a senior legal figure is particularly damaging, coming just hours after the Justice Secretary, Robert Buckland, defended the legislation and said he would only resign if the law was broken in a way he found unacceptable.
Mr Cox’s onslaught also followed his successor as attorney general, fellow Brexiteer Suella Braverman, facing accusations at a stormy meeting of the Bar Council, the professional association for barristers, of sacrificing the UK’s reputation.
In his Times article under the headline “Honour rests on keeping our word”, Mr Cox wrote: “When the Queen’s minister gives his word, on her behalf, it should be axiomatic that he will keep it, even if the consequences are unpalatable.
“By doing so he pledges the faith, honour and credit of this nation and it diminishes the standing and reputation of Britain in the world if it should be seen to be otherwise.
“The Withdrawal Agreement and its attendant Northern Ireland Protocol represent treaty obligations of this country to which the government, in which I had the honour to serve as attorney general, gave its solemn and binding word.
“It is, therefore, obliged to accept all the ordinary and foreseeable consequences of the implementation of that agreement.
“Those manifest consequences included the inevitable application of EU tariffs and customs procedures to certain goods entering Northern Ireland from Great Britain and of the EU’s state aid regime to the province.
“There can be no doubt that these were the known, unpalatable but inescapable, implications of the agreement. They included a duty to interpret and execute both the agreement and the protocol in good faith.”
And he concluded: “What ministers should not do, however provoked or frustrated they may feel, is to take or use powers permanently and unilaterally to rewrite portions of an agreement into which this country freely entered just a few months ago.
“Therefore, if the government does not urgently and effectively dispel the impression that it intends to do so, I shall have no choice but to withhold my support for this bill. I am a strong supporter of this government and of Brexit and I am deeply saddened to have to say this.
“We, the British government and parliament, have given our word. Our honour, our credibility, our self-respect and our future influence in the world all rest upon us keeping that word. Nothing less is worthy of Britain.”
A Tory MP since 2005, Mr Cox is one of Westminster’s most flamboyant MPs, known for his booming voice in the Commons chamber and his rousing warm-up speech introducing Theresa May at the 2018 Tory conference.
His dramatic intervention will embolden those Tory MPs who claim the bill rips up Mr Johnson’s own Brexit Withdrawal Agreement, despite government ministers insisting it is simply a “safety net” or “insurance policy”.
Coming at the start of a week in which Commons business will be dominated by debates on the Internal Market Bill, Mr Cox’s assault is likely to swell the numbers of Conservative rebels and be quoted at length by the bill’s opponents.
Besides facing a backbench mutiny, Mr Johnson has been attacked by former premiers Theresa May, Tony Blair and Sir John Major and leading Tory Brexiteers Lord Howard and Lord Lamont.
Day one of the Commons clashes sees MPs debate the bill at its second reading, with votes at 10pm on whether it continues to line-by-line scrutiny in a four-day committee stage.
Labour and the smaller parties, including the Scottish National Party and Liberal Democrats, have tabled amendments declining to give the bill a second reading, though it is likely only Labour’s will be voted on.
Labour’s amendment states: “This bill undermines the Withdrawal Agreement already agreed by parliament, reopens discussion about the Northern Ireland Protocol that has already been settled, breaches international law, undermines the devolution settlements and would tarnish the UK’s global reputation as a law-abiding nation and the UK’s ability to enforce other international trade deals and protect jobs and the economy.”
The smaller parties’ amendment states: “This House declines to give a second reading to the United Kingdom Internal Market Bill because it breaks international law and is contrary to the established devolution settlement.”
During the Commons committee stage, the government faces numerous attempts to amend the bill, including a move by senior Tory MPs led by barrister Sir Bob Neill, who chairs the Justice Select Committee, to add a “parliamentary lock” – effectively a veto – on any changes to the Withdrawal Agreement.
And after the attacks on the bill already by pro-Brexit grandees Lord Howard and Lord Lamont, the bill is also likely to be mauled by Conservative as well as opposition and crossbench peers in the House of Lords.