Britain's embattled Prime Minister Boris Johnson vowed on Tuesday to plough on with propping up the economy and Ukraine, but was urged by a Conservative predecessor to quit and save the nation from further "agonies".

Addressing his cabinet a day after narrowly fending off a no-confidence vote from his own Conservative MPs, Johnson said: "We're able now to draw a line under the issues that our opponents want to talk about."

The vote came after public and political outrage at lockdown-breaking parties in Downing Street
The vote came after public and political outrage at lockdown-breaking parties in Downing Street AFP / Niklas HALLE'N

But most critics and commentators disagreed, with many characterising the margin of his win -- 211 votes to 148 -- as a "Pyrrhic" victory that left the Tory leader drained of much authority.

Johnson's former employers at the Daily Telegraph branded it "a hollow victory that tears Tories apart".

Tories were met with calls for them to vote against the prime minister
Tories were met with calls for them to vote against the prime minister AFP / Niklas HALLE'N

"Party's over, Boris," headlined the Daily Mirror, in a nod to a series of lockdown-busting parties held in Downing Street, which saw Johnson fined by police and drew outrage from voters.

The prime minister's team tried to regain the offensive by pointing to a setpiece speech expected in the coming days on new economic support measures, as Britons struggle with a cost-of-living crisis.

However, a cabinet reshuffle to replenish his team of Brexit loyalists is not "currently" on the cards, Johnson's spokesman said.

Boris Johnson won a confidence vote but his star is fading after many of his MPs refused to back him
Boris Johnson won a confidence vote but his star is fading after many of his MPs refused to back him AFP / Ben STANSALL

Nor is a snap general election, the prime minister said after the vote, pointing to the pressing need for government unity in the face of Russia's invasion of Ukraine.

Johnson won a landslide general election victory in December 2019 but has endured a torrid time in power since
Johnson won a landslide general election victory in December 2019 but has endured a torrid time in power since POOL via AFP / Alberto Pezzali

Britain has been at the forefront of European military support for the government of Ukrainian President Volodymyr Zelensky, who spoke by phone to Johnson in the hours before Monday's Conservative ballot.

Approval rating for Johnson's government
Approval rating for Johnson's government AFP / Gal ROMA

At an online event on Tuesday hosted by the Financial Times, Zelensky said he was "very happy" that Johnson had survived the vote.

"Boris Johnson is a true friend of Ukraine," the president added, speaking through a translator.

But at home, many question whether Johnson can recover voters' trust, as the party braces for two Westminster by-elections this month and an upcoming investigation by MPs into whether he lied to parliament over "Partygate".

Boris Johnson won a confidence vote but his star is fading after many of his MPs refused to back him
Boris Johnson won a confidence vote but his star is fading after many of his MPs refused to back him AFP / Ben STANSALL

Even without any obvious candidate to succeed him, former Tory party leader William Hague argued that Johnson should now "look for an honourable exit".

Comparing Monday's margin to votes that ultimately toppled Johnson's predecessors Margaret Thatcher and Theresa May, Hague said it showed "a greater level of rejection than any Tory leader has ever endured and survived".

"Deep inside, he should recognise that, and turn his mind to getting out in a way that spares party and country such agonies and uncertainties," Hague wrote in The Times.

But in his personal life, populist politics and bombastic style, Johnson is unlike previous Conservative leaders, and his camp spent Monday arguing that even a majority of one would suffice.

Nevertheless, according to King's College London politics professor Anand Menon, the scale of the revolt "constitutes a crisis for Downing Street".

"I think there's very little doubt that the vulnerability of the prime minister is going to be the single greatest factor shaping what this government does for the foreseeable future," Menon told AFP.

Johnson, 57, needed the backing of 180 of the 359 Conservatives MPs to survive the vote.

Most of Johnson's cabinet publicly backed him in the secret ballot. But more than 40 percent of the parliamentary party did not.

Under current Tory rules, the prime minister cannot be challenged again for a year, which leaves little time for any new leader to emerge before the next general election due by 2024.

Senior backbencher Tobias Ellwood, who voted against Johnson, said the prime minister was living on borrowing time.

"I think we're talking a matter of months, up to party conference (in October)," he told Sky News.