Boris Johnson accused the EU of preparing to go to “extreme and unreasonable lengths” in Brexit talks as he defended breaching international law amid a mounting rebellion from Tory backbenchers.
The former chancellor, Sajid Javid, became the most senior of the prime minister’s past cabinet colleagues to say they could not support the UK internal market bill in a Commons vote tonight.
Javid joined two former Conservative attorney generals, Jeremy Wright and Sir Geoffrey Cox. David Cameron, one of Johnson’s predecessors, had earlier expressed “misgivings” about the creation of powers to row back on elements of the withdrawal agreement involving Northern Ireland. All five living former prime ministers have now expressed concern about the bill.
More than 20 Tory MPs are expected to withhold support for the bill but most will abstain unless the government makes concessions on giving parliament a vote on the new powers ahead of the division tonight.
Whips told some MPs the threat of withdrawing the Conservative whip had not been ruled out if they rebelled.
In a nod to some angry MPs, Johnson said he would never invoke the controversial powers in the internal market bill if a Brexit trade deal was reached with the EU. He said the UK would “simultaneously pursue every possible redress under international law, as provided for in the [Northern Ireland] protocol” – a measure suggested by Cox.
Opening the debate in the Commons, the prime minister claimed the EU was willing to “use the Northern Ireland protocol in a way that goes well beyond common sense, simply to exert leverage against the UK in our negotiations for a free trade agreement”.
Johnson said the measures in the bill – which would hand unilateral powers to ministers in key areas yet to be agreed with the EU, breaching the terms of the treaty agreed in January – were “a protection, it’s a safety net, it’s in an insurance policy, and it is a very sensible measure”.
He said threats from the EU, which the bloc has denied, had made the legislation necessary, claiming the bloc could prevent food exports from Great Britain to Northern Ireland.
That claim drew incredulity from the shadow business secretary, Ed Miliband, who responded for Labour. He said the bill did “precisely nothing” to address that issue, offering mockingly to give way to Johnson in the Commons if he had found anything in the bill that dealt with the “supposed threat”.
“He didn’t read the protocol, he hasn’t read the bill,” Miliband said. “What incompetence, what failure of governance, and how dare he try and blame everyone else? This is his deal, it’s his mess, it’s his failure.”
Intervening in Johnson’s speech, Wright raised the ministerial code which he said bounds ministers to respect international law. Earlier the former attorney general had said he along with many others, were “profoundly disturbed by what’s going on”.
Two former barristers – Cox and Rehman Chishti, who quit as the special envoy on religious freedom – also told the government they would not back the bill, along with former solicitor Gary Streeter.
“There is concern among some lawyers in parliament about what effect this would have on their practice after they leave parliament – the bar has made its view very clear,” one MP said.
The debate also saw the first of the 2019-intake of Tory MPs decline to back the bill. Imran Ahmad Khan, who represents Wakefield, said: “Moral authority is hard-earned and easily lost.”
Javid, who quit the cabinet earlier this year, said it was not clear why international law had to be broken and that he was “regretfully unable to support the UK internal market bill” unamended. He added the UK should wait until it was clear the EU intended to act in bad faith and until then use safeguards already enshrined in the withdrawal agreement.
Others planning to abstain include Tobias Ellwood, the chair of the defence select committee, who said: “Everything is getting very high-octane, and the collateral damage to Britain is reaching the US Congress, where people are bewildered we are going down this avenue.
“Many of us are conflicted because I came into politics to further Britain’s place on the international stage, and now we are at a time where there is an absence of political leadership, and we can’t hold our heads up high if we are being seen to challenge international law.”
Most MPs with concerns about the bill will be expected to abstain rather than vote against, saving their ire for votes next week where amendments will be tabled. Asked whether Tory MPs who rebelled on Monday night could lose the whip, Johnson’s spokesman stressed it was “critical” that Conservatives backed the bill.
An amendment next week has been put forward by the chair of the justice select committee, Bob Neill – another former barrister. It would require parliamentary approval before any future decision could be made by the government to disapply the terms of the Northern Ireland protocol in the withdrawal agreement.
Those backing the Neill amendment include the former cabinet minister Damian Green, the QC and former justice minister Oliver Heald, the Northern Ireland select committee chair, Simon Hoare, and Damian Collins, former chair of the culture select committee, who are all expected to withhold support for the bill.
Others expressing serious concerns were the chair of the foreign affairs committee Tom Tugendhat, former transport minister George Freeman and the veteran Tory Sir Roger Gale who said: “An Englishman’s word used to be his bond. Under Johnson that is not so.”
One senior backbencher accused the whips of scare tactics. “Unfortunately this is being framed as being pro or against Brexit again, even whether you are patriotic,” the MP said. “Cox’s intervention should prevent it descending into those shallow waters.
“They are now leaning heavily on loyalty to the prime minister – and there are many people who do want to go back into government and they will be tested today, there’s no question.”
There is consternation even among loyal long-serving Conservatives who are planning to back the government. One former cabinet minister said they would only back the bill “through gritted teeth”.
On Monday, Cameron said: “Passing an act of parliament and then going on to break an international treaty obligation is the very, very last thing you should contemplate. It should be an absolute final resort. So, I do have misgivings about what’s being proposed.”
The former Labour prime ministers Gordon Brown and Tony Blair and the former Conservative prime minister John Major all said the bill risked the UK’s international obligation. Johnson’s predecessor, Theresa May, has also made clear in parliament she is concerned about the implications of the bill.