When Boris Johnson was deep in the quagmire of the partygate scandal, his rival Sir Keir Starmer said the country needed “a serious leader for serious times” and called on the prime minister to go. 

For weeks, Mr Johnson was hanging on by a thread, his future being openly discussed as the Metropolitan Police launched a criminal investigation into him and his Downing Street staff.

Then President Putin invaded Ukraine, and everything changed.

Fury over parties in Downing Street paled into insignificance as our TV screens filled with barely watchable footage of unspeakable violence and human suffering in Ukraine.

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Boris Johnson and his fellow Western leaders now have to lead their citizens and countries through a crisis that is incomprehensible, without precedent and with no end in sight.

From these most horrific of circumstances has come an opportunity for the prime minister to redeem himself in the eyes of the British public. For Mr Johnson, there is an opportunity for redemption, to prove to voters that he can meet the gravity of this moment.

And the moment is deeply grave. When I sat down with him in Liverpool to discuss Ukraine and what comes next, the prime minister predicted the “cynical barbaric” Russian government may end up using chemical weapons.

Mr Johnson said his conversations with Ukraine’s President Zelenskyy over the West’s unwillingness to implement a no-fly zone over Ukraine to protect civilians were “deeply upsetting” and “agonising”.

But he also said that such a move would put the UK into direct military conflict with Russia, and that was “a very difficult line to cross”.

While the prime minister said “Putin must fail”, what that failure looks like or when it happens, he could not predict. He told me that Mr Putin “has himself made it very difficult to find an off ramp”.

Mr Johnson, who hosted the Dutch, Canadian and Polish prime ministers in London this week, is using this war to step onto the world stage and try to prove himself as a capable wartime leader, but there has been criticism of the domestic leadership around refugees and sanctions on Russian oligarchs.

As one senior Conservative MP put it to me the other night: “Boris talks a good game but there is a mismatch between rhetoric and reality and his not delivering on the policies around refugees or Russian money.”

The Number 10 team moved on Thursday to close that gap, finally sanctioning Roman Abramovich and six other Russian oligarchs with a full asset freeze and travel ban, as well as imposing the same sanctions on Oleg Deripaska, the founder of London-listed metals group EN+, and Igor Sechin, chief executive of Rosneft and one of Mr Putin’s closest allies.

On its handling of refugees, the Johnson administration has also been mired in cross-party controversy. It has issued just 1,000 visas in the first 10 days of war, prompting SNP Westminster leader Ian Blackford to accuse the government of creating a “hostile environment” for those fleeing Ukraine.

Earlier, the government announced it would simplify the application process for those with passports hoping to qualify for the “family reunion” route, by removing the need for in-person appointments.

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In his interview with me, the prime minister revealed that on Monday the Levelling Up secretary Michael Gove will outline the details of the humanitarian visa route, which will allow Ukrainians without family already in the UK to also apply for asylum.

But as for waiving visas as the EU has done, the PM won’t be moved. “I think people want us to have checks,” he told me. “I think people want us to be generous, but they also want us to be careful.”

The question of the treatment of refugees is an open flank for a government that is under heavy scrutiny from the public and Conservative MPs over the competence of the Johnson administration, as so devastatingly exposed during the partygate scandal and its fall out.

The PM brushed off criticisms when I asked him about this, but it is a policy which could unravel and reflect badly on him – which helps explain why he appointed former MP and businessman Richard Harrington as refugees minister.

The other glaring danger for the PM at home is the sheer scale of the cost of Mr Putin’s war on already stretched finances of consumers, amid predictions rising global energy prices could push inflation to above 8 per cent.

This could result in average incomes falling by 4 per cent – costing average households £1,000. One senior cabinet figure suggested to me household energy bills could go up by an eye watering £3,000.

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This is the economic pain the PM says it will be necessary to endure in order to defeat Mr Putin – admitting it was going to be a “bumpy few months”, but insisting weaning ourselves off Russian oil and gas was the right thing to do in order to stop the Russia leader being able to blackmail the West in the future.

On a personal level, Mr Putin’s war has helped Mr Johnson turn the page on a particularly torturous period where he was clearly at a low ebb.

Whatever the findings of the Met Police, it seems pretty clear to me that the PM will neither offer to resign nor be forced out by his party when the West is trying to handle a war in Europe – indeed Scottish Conservative leader Douglas Ross has announced he has now withdrawn the letter he submitted calling for Mr Johnson’s resignation.

But the job of PM has never been harder as we face the horror of a Russia-Ukraine war we seem powerless to stop, and a cost of living crisis that millions will find very hard to bear.

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