Sir Keir Starmer has made a forthright defence of the European Convention on Human Rights (ECHR) and said those calling for the country to leave it were “not serious” people.

Nigel Farage, the leader of Reform UK, said that Britain would leave the convention if he won the next election “no ifs, no buts”. The Human Rights Act, which enshrines the convention in law, would be scrapped and replaced with a British bill of rights.

Kemi Badenoch, the Tory leader, is also expected to back leaving the convention at the Conservative Party conference in October but said simply scrapping the treaty was “not a plan in itself”.

Nigel Farage speaking at a Reform UK policy announcement.

Nigel Farage said he would pull Britain out of the ECHR if Reform won the next election

LEON NEAL/GETTY IMAGES

Lord Blunkett, a former Labour home secretary, has suggested Britain should suspend its membership of the convention in order to grasp control of the small-boats crisis.

However, Starmer, a former human rights lawyer, is resolutely opposed to either suspending or leaving the convention. He believes that doing so would place Britain in the same “camp” as Russia and Belarus.

After Reform revealed a raft of legal changes that Farage claimed would allow Britain to control immigration, including scrapping the ECHR, the prime minister’s official spokesman said: “Let’s be clear: the ECHR underpins key international agreements on trade, security, migration and the Good Friday agreement. Anyone who is proposing to renegotiate the Good Friday agreement is not serious.”

He said: “We’re focused on the very serious policies to address this issue rather than a return to the gimmicks, the slogans, the chaos of the previous government.”

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Last week Blunkett said Britain should follow the example of countries such as Germany and suggested Starmer suspend parts of the ECHR for a temporary period — potentially six months — in order to clear the backlog of asylum appeals.

Many appeals are heard on two key sections of the convention: Articles 3 and 8, which protect against breaches of rights to a family life or to persecution if people are returned to their home country.

Blunkett said: “I think we are going to have to look at not necessarily pulling out of the ECHR or 1951 UN [Refugee] Convention but perhaps temporarily suspending particular elements of it until we can actually get a grip.”

But the government maintained its position that the ECHR should instead be reformed.

Portrait of Lord David Blunkett.

Lord Blunkett, a former Labour home secretary, says Britain should suspend its membership of the ECHR to deal with the small boats crisis

JOSHUA BRATT FOR THE SUNDAY TIMES

Matthew Pennycook, the housing minister, said: “We don’t think that’s in our national interest. It underpins a series of incredibly important agreements, including the Good Friday agreement.

“We want to reform it in conjunction with European partners, not by withdrawing from it unilaterally or suspending it. That would put us in a club with Russia and Belarus.”

Starmer’s spokesman, in response to Farage, said: “Reforming international law takes graft and not just simple soundbites.”

Starmer did not rule out Farage’s plan to secure returns deals with countries such as Afghanistan and Eritrea, however, despite their human rights records.

Farage said on Tuesday that Reform UK would attempt to sign deals with the two countries, plus Iran, despite concerns about their human rights records. He failed to answer when asked how much he would be prepared to pay to Iran and the Taliban to take deportees back.

Asked whether the government could seek deals with Afghanistan and Eritrea, Starmer’s spokesman said: “We’re not going to take anything off the table in terms of striking returns agreements with countries around the world. We clearly want to return people who have no right to be here.”

The government secured a deal with Iraq last week.

Badenoch, meanwhile, accused Farage of “copying our homework” with his immigration proposals. She said the only workable parts of Farage’s pledges had come from Conservative policy and that Reform was “not doing the thinking” required to deliver.

Badenoch refused to say how many migrants a future Conservative administration would seek to deport. “It’s not about the numbers. It is about making sure that we control our borders and we get all the people who are breaking our laws and coming here illegally out of the country,” she told journalists on a visit to Chelmsford on Tuesday.

“Imitation is the sincerest form of flattery,” she added. “We put out a deportation bill in May. The stuff that actually works in what [Farage] said has come from there.”

The Tory “bill” announced earlier this year included plans to disapply the Human Rights Act from all immigration-related matters and “introducing powers to deport all foreign criminals”. Badenoch has ordered a review into whether the UK should leave the ECHR, which she said would report back before the Tory conference.

Asked about Farage’s pledge, she said: “Saying you’re going to leave the ECHR is not a plan. From what Reform has announced today, they haven’t done the thinking, they’ve just copied our homework, but they don’t understand the reasons behind them.”