Boris Johnson has been warned he will struggle to get controversial legislation – which seeks to override the Brexit withdrawal deal – through the House of Lords.
Lord Howard of Lympne, the former Conservative Party leader, told Sky News he would be “very surprised” if the proposed UK Internal Market Bill was passed by peers.
The Brexit-backing peer is the third ex-Tory leader – after Sir John Major and Theresa May – to condemn the prime minister’s plan to use the legislation to alter key elements of the UK’s Withdrawal Agreement.
Mr Johnson himself struck the Withdrawal Agreement last year before formally signing the deal in January.
But he is now seeking, through the bill, to empower ministers to set it aside.
Lord Howard described the government’s admission that the proposed legislation would break international law as a “very, very sad day”.
“We have a reputation for probity, for upholding the rule of law,” he told Kay Burley.
“And it’s a reputation that is very precious and that ought to be safeguarded.
“I’m afraid it was severely damaged.”
Lord Howard, who once sacked Mr Johnson from the Conservative front bench following allegations about the now prime minister’s private life, added there was “no mandate from the British people to break treaties”.
The government is facing mounting anger from senior Tories, as well as fury and a threat of legal action from the European Union, over the legislation.
And Lord Howard predicted Mr Johnson would face a parliamentary battle if he ploughs ahead with his plans.
“I’m sure that many of my Conservative colleagues will be joining me in opposing it,” he said.
“And, of course, the Conservative Party in the House of Lords doesn’t have a majority anyway.
“So, I’d be very surprised if it gets through the House of Lords.”
Although the prime minister enjoys an 80-strong majority in the House of Commons, he is also facing a possible revolt among Tory MPs.
Mr Johnson was due to speak to Conservative MPs on Zoom about the bill on Friday evening.
Unhappy Conservative backbenchers have tabled an amendment to the legislation that would try to block the government from overriding the Withdrawal Agreement without parliament’s support.
Sir Bob Neill, who has tabled the amendment with the backing of fellow Tory former ministers Damian Green and Oliver Heald, told Times Radio: “I hope it’s at least an indication as a government that really, you need to think very hard and carefully about going down this route.
“For heaven’s sake, try and find some other way.”
Sir Bob played down the prospect of Tory rebels, who are reported to number up to 30, losing the Tory whip by voting against the government’s proposed legislation.
But he signalled he would be ready to be thrown out the Conservative parliamentary party if necessary.
Sir Roger Gale also indicated he is ready to lose the Conservative whip in order to vote against the bill.
“I shall do what I have to do on the basis of principle,” he told Sky News.
“And the principle is that this United Kingdom keeps its word internationally.”
Last year, Mr Johnson expelled 21 Conservative MPs from the parliamentary party for voting against his Brexit plans.
The government has argued the UK Internal Market Bill is “critical” to ensuring the unfettered access for goods from Northern Ireland to the rest of the UK, and to protect the Good Friday Agreement.
Ahead of the bill being debated by MPs in the Commons next week, business minister Nadhim Zahawi told Sky News he and his fellow ministers would “look forward to outlining exactly why we’re taking these precautionary measures”.
“What we’re taking is, really, an insurance policy to make sure that… if there is no deal, we will not allow adverse impacts of that on the people of Northern Ireland, of all communities,” he told Kay Burley.
“That cannot be the right thing to do and, next week, parliamentarians, the country, will be able to scrutinise what we are saying and how we aim to do this.”
Mr Zahawi added that “ambiguities” remained in the Withdrawal Agreement and its provisions for the Irish border – known as the Northern Ireland Protocol – due to the deal being signed “at pace” last year, which necessitated the new legislation.
“What we are saying is, this is is not about if we implement them, this is about how we implement them,” he said.
But Sir Simon Fraser, the former head of the Foreign Office, accused the UK government of throwing a “bombshell” into continuing trade talks on a future EU-UK relationship with the proposed legislation.
He told Sky News the proposed legislation “unpicks unilaterally significant parts of the Withdrawal Agreement”.
“It is a very significant potential disapplication of important parts of that agreement,” Sir Simon added.
“The fact they’re saying they’re doing this because they signed the agreement in a hurry and didn’t realise its implications is hardly a convincing argument.”