Britain's government Wednesday refused to rule out abandoning a European human rights pact after a judge dramatically blocked its plan to fly asylum-seekers to Rwanda, sparking fury among Conservatives.

The last-gasp intervention by the European Court of Human Rights (ECHR) forced the government to cancel the first flight on Tuesday night, after the number of claimants aboard had already been whittled down by UK legal challenges.

Interior minister Priti Patel, however, told parliament the government "will not be deterred from doing the right thing" and that plans for further flights "have already begun".

She attacked the "usual suspects" among lawyers' firms and rights groups for defying the "will of the British people", as well as "evil" gangs behind a flourishing cross-Channel trade in migrants.

The ECHR is unrelated to the European Union, which Britain left in January 2020.

But Tory backbenchers, fresh from rebelling in large numbers against Prime Minister Boris Johnson's leadership, said the ruling infringed on British sovereignty.

"Yes, let's withdraw from European Court of Human Rights and stop their meddling in British law," MP Andrea Jenkyns tweeted, echoing others in the party and banner headlines in right-wing newspapers.

The government had chartered a plane to take migrants to Rwanda but was stopped by a European court ruling on Tuesday night
The government had chartered a plane to take migrants to Rwanda but was stopped by a European court ruling on Tuesday night

The government's top law officer, attorney general Suella Braverman, said many in Britain would be frustrated at the role played by a "foreign court".

"We are definitely open to assessing all options available as to what our relationship should be, going forward, with the European Court of Human Rights," she told BBC radio.

The European convention was enshrined in UK law in 1998 by the Labour government of Tony Blair.

It notably underpins the Good Friday Agreement of the same year, which brought peace to Northern Ireland after three decades of bloodshed.

The prime minister's spokesman said "we keep all options on the table" to facilitate the deportation plan.

But he added: "We would do nothing that would in any way jeopardise the Good Friday Agreement."

Johnson's government is already in a bust-up with the EU over post-Brexit trading rules for Northern Ireland, and critics allege it is picking a separate fight over asylum-seekers to distract from economic trouble and political scandals.

The convention has been used frequently by human rights lawyers to frustrate Johnson and Patel's hardline policy against illegal migrants.

Last month, in the "Queen's Speech" opening a new session of parliament, the government committed to replacing the 1998 act with a new bill of rights.

Home Secretary Priti Patel insists the policy is legal and vowed to press on
Home Secretary Priti Patel insists the policy is legal and vowed to press on

Johnson's own maternal grandfather, James Fawcett, helped to write the European convention and was the commission's president for a decade in the years after World War II.

Anneke Campbell, a cousin to Johnson's late mother, wrote in the Byline Times newspaper last week that Fawcett would have been "appalled" at the government's actions.

Under the UK's agreement with Rwanda, all migrants arriving illegally in Britain are liable to be sent to the East African nation thousands of miles away for processing and settlement.

More than 10,000 migrants have crossed the Channel from northern France since the start of the year.

On Wednesday, officials said, around 150 more people including two dozen children were brought ashore in the English port of Dover from two dinghies that appeared partially deflated.

Enver Solomon, head of Britain's Refugee Council, said the ever-rising numbers of crossings disproved the government's claims that it was putting people-smugglers out of business.

Its determination to press on with the Rwanda plan heightened "the human suffering, distress, and chaos the threat of removal will cause with far-reaching consequences for desperate people", he said.

The ECHR, ruling in favour of an Iraqi claimant, said his expulsion should wait until London's High Court has taken a final decision on the policy's legality at a hearing next month.

The policy has sparked widespread protests and a wave of legal challenges
The policy has sparked widespread protests and a wave of legal challenges

"Rwanda remains fully committed to making this partnership work," government spokeswoman Yolande Makolo told AFP.

Number of arrivals in UK on small boats
Number of arrivals in UK on small boats