David Cameron has become the third former Conservative prime minister to express disquiet about Boris Johnson’s proposal to breach international law by unilaterally redrafting part of the Brexit deal with the EU, saying he had “misgivings” about the idea.
In comments on Monday, before MPs begin debating the internal market bill, which sets out the plans, 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.”
Cameron said he also had to consider that the UK was “in a vital negotiation with the EU to get a deal and I think we have to keep that context, that big prize in mind”.
He added: “And that’s why I have perhaps held back from saying more up to now.”
Former Conservative leaders William Hague and Michael Howard have also expressed reservations about the bill.
The comments come amid a potential Tory backbench rebellion about the plan, with the former attorney general Geoffrey Cox saying on Monday that breaking international law risked causing “very long-term and permanent damage to this country’s reputation”.
Ahead of the second reading of the bill, the first opportunity MPs will have to debate it, Cox said he understood government arguments that the EU was acting in bad faith over the Brexit withdrawal agreement.
“But what you can’t do, and what I think is wrong, is to abandon an agreement, to rewrite unilaterally parts of an agreement, which you only signed nine months ago, and to which we have given our solemn word,” he told Times Radio.
He added: “The breaking of the law, ultimately, leads to very long-term and permanent damage to this country’s reputation. And it’s also a question of honour, to me. We signed up, we knew what we were signing. We simply can’t seek to nullify those ordinary consequences of doing that.”
Cox did, however, indicate that while he could not support the bill as it stood, this could change: “If the government were to say that these powers will only be used in these specific circumstances, where it would be lawful to act in this way, then that might well be a different position. But I haven’t had those assurances yet.”
Speaking earlier, the policing minister, Kit Malthouse, said that even with his job he had no worries about supporting a measure which potentially broke international law.
“I’m policing minister, so I’m responsible for the criminal law, and this is obviously a civil matter and an international law matter,” he told BBC1’s Breakfast programme.
Malthouse argued the action was needed because the EU had threatened to potentially threaten food exports to Northern Ireland from Great Britain, which Brussels has rejected.
He said: “The lawyers will bat it backwards and forwards, I have absolutely no doubt about that. But from my point of view as a non-lawyer, I’m looking at the practical effect.”
Malthouse rejected the idea that the government planning to break the law could prompt people to ignore UK laws, for example new rules on coronavirus: “We think it is a good example.”
But Labour’s shadow business secretary, Ed Miliband, rejected this: “How can we on the one hand be saying, you’ve got to obey the law, which we all say rightly as legislators, and then the government comes along and says, well it’s OK for us to breaking the law because it’s specific and limited. We can’t be having that.”
He said the arguments were about international law, not Brexit: “It’s really important to make this point that this isn’t about remain or leave. That argument has been settled.
“We’ve left the European Union. We lost the general election on those issues. We’re not going back.”