The Reform UK leader has been criticised for saying a government headed by his party would look to renegotiate the Good Friday Agreement as part of its plan to stop small boat crossings to England.

Nigel Farage made the claim at a news conference where he announced moves to deport up to 600,000 asylum seekers in its first parliament.

He said he would leave the European Convention on Human Rights – which helps underpin the agreement – and replace it with a British Bill of Rights applying only to British citizens and those who have a legal right to live in the UK.

A Downing Street spokesperson said: “Anyone who is proposing to renegotiate the Good Friday Agreement is not serious.”

When asked if he was concerned that leaving the ECHR could jeopardise the Good Friday Agreement, Farage replied: “Yeah I mean look, Blair of course wrote the ECHR into everything.

“He wrote it into everything to try and embed it deeply in British law.

“Can we renegotiate the Good Friday Agreement to get the ECHR out of it? Yes.

“Is that something that can happen very, very quickly? No, it will take longer. It will take longer.

“So unfortunately, and for a variety of reasons – previous governments have placed Northern Ireland, I’m afraid, in a different position to the rest of the United Kingdom, something that we vigorously opposed – it will take a little bit longer with Northern Ireland.”

But Downing Street was quick to rule out leaving the ECHR with the prime minister’s spokesman saying: “The ECHR underpins key international agreements , trade, security and migration and the Good Friday Agreement.”

Nigel Farage is not the first would-be British prime minister to talk about leaving the European Convention on Human Rights.

The Tories have been toying with the idea for years and still are.

The problem is they keep coming up against the rock of peace in Northern Ireland and the impact such a move would have on the Good Friday Agreement.

When questioned directly about potentially jeopardising the agreement, Farage suddenly sounded less sure footed saying “it will take a little bit longer with Northern Ireland”.

It is not immediately clear what that means.

There’s also the little matter of actually winning the next British general election.

Reform are currently ahead in the polls.

But the election is potentially more than three and a half years away – a very long time indeed in politics

Farage was also criticised by Conservative leader Kemi Badenoch who accused Reform UK of “copying our homework”.

She said her party would announce at its annual conference in October whether it will leave or disapply the ECHR or other treaties that impact the UK’s ability to deal with the issue of small boat arrivals.

Former SDLP leader Colum Eastwood said the plan announced by Farage was “another rerun of the tired, empty and undeliverable rhetoric of Brexiteers who had no answers for tough questions on what that would mean for the legal framework of the Good Friday Agreement.”

He said the “narrow vision” of Britain’s future espoused by Farage and his party “is making the case for a new Ireland for those who want something different”.

Eastwood added: “People on this island see the turmoil in Britain and the narrow, divisive vision of the future being promoted by people like Farage and they increasingly want no part of it.”