Critics have blamed this on several errors made early on, from going into lockdown too late and making a mess of testing to poor government communications.

However, of late, Johnson's fortunes appear to have turned. On Monday, the Prime Minister was able to reveal a roadmap that would take England out of lockdown before the end of June.

Johnson would not have been able to deliver this good news had the UK's vaccine rollout not gone so remarkably well to date. As things stand, the UK has administered more than 18.5 million doses, or 27 per 100 people. Compare this to other European giants like France and Germany, who have each managed only six per 100, and a very favorable narrative emerges for Johnson.

The UK, no longer a member of the European Union, opted not to work with its European partners in procuring or approving vaccines. As a result, it was able to negotiate contracts and approve vaccines for use more quickly.

"If you wanted a single demonstration of why Brexit was important, you've got it. If we were still in the EU now some people would be dead who are not. It's nothing to crow about, it's just true," said David Davis, a veteran lawmaker and former Brexit secretary.

There are other reasons the UK got ahead, not least Johnson's massive spending spree when it came to procuring vaccines. Of the 357 million vaccines the UK has purchased, the largest contract by far is with British-Swedish drugmaker AstraZeneca, whose vaccine was developed in partnership with Oxford,
Britain's oldest university and Johnson's alma mater. The bet on Oxford and AstraZeneca paid off spectacularly, and the UK was the first country to authorize the vaccine for use in all adults.

So proud were Brits of their homegrown vaccine that Paul Williams, a GP and former opposition lawmaker, tweeted that patients had turned down vaccines from Pfizer, saying they would "wait for the English one." Johnson and his government, though proud of the AstraZeneca vaccine to the extent officials confirmed to CNN it considered plastering a Union Jack on the vials, have publicly encouraged Brits to accept any vaccine offered by their doctor.

It's a different story on the other side of the Channel, where the European Union was slower to authorize vaccines for use, then waged a war of words with AstraZeneca over delays in supply in late January.

As the spat overheated, some European leaders went as far as publicly casting doubt on the effectiveness of the vaccine.

French President Emmanuel Macron described the AstraZeneca vaccine as "quasi-ineffective" in older people, saying "the first results are not encouraging for those over 60-65 years old." The claim was disputed by multiple scientists.

The day before, Germany officials declined to authorize the vaccine for use in people over 65, citing a lack of sufficient data for that age group in the drugmaker's trials. France, Spain, Italy and others followed suit, limiting authorization of the vaccine to younger segments of the population.

But this week, Scottish scientists published new research showing that AstraZeneca's vaccine reduced the overall risk of being admitted to hospital by up to 94% four weeks after having a single dose, and that one shot was highly effective in preventing hospitalizations in elderly populations too.

The study not only further vindicated the UK's authorization of the vaccine for all adults, but also its strategy of delaying second doses in order to provide partial protection to as many people as possible.

Now, European regulators are reconsidering their restrictions on who can get the shot. France's health ministry told CNN on Wednesday that it was is "likely" to extend its AstraZeneca vaccine age range guidance in the wake of the Scottish study.

But the crisis over delayed vaccine supply continues in Europe; one EU official told Reuters on Tuesday that AstraZeneca had informed the bloc it would only be able to deliver less than half of the expected doses in the second quarter.

There also fears that the EU's bruising public battle with AstraZeneca has undermined confidence in the vaccine, and signs that some European countries appear to be struggling to convince their citizens to take the shot.

The spokesman for German Chancellor Angela Merkel took the extraordinary step of tweeting that the "AstraZeneca [vaccine] is both safe and highly effective" earlier this week, following reports that Germans were turning it down.

Germany has administered just 15% of its available AstraZeneca shots, according to the health ministry, partly because the country is only administering it to people under 65 and most of those eligible for vaccination at this point are older. To solve the issue, Germany has reworked its vaccinations schedule and will start vaccinating teachers sooner. But some also see the AstraZeneca vaccine as a lower quality shot, because of its slightly lower efficacy rates compared to other authorized vaccines.

"It's extremely worrying. Any doubt in the confidence of vaccines means the potential need for a complete overhaul in your rollout strategy. And during a pandemic, you are in a constant battle to keep public confidence high," said Cathryn Cluver Ashbrook, executive director of the Project on Europe and the Transatlantic Relationship at the Harvard Kennedy School.

European Commission President Ursula von der Leyen, while admitting her own failure on Europe's vaccine rollout, has suggested that while the UK had moved faster, it had done so irresponsibly and put its own citizens at risk.

"Yes, Europe left it later, but it was the right decision. I remind you that a vaccine is the injection of an active biological substance into a healthy body. We are talking about mass vaccination here, it is a gigantic responsibility," she said in early February. This week, however, von der Leyen rushed to vocally support the AstraZeneca vaccine, saying she would take it "without a second thought."

Boris Johnson has kept relatively quiet through it all, content to enjoy a propaganda win over the EU at a time when other problems are mounting at home, not least disruptions in trade due to Brexit.

"Rewind 12 months. If you told Johnson that if he rubbed a lamp, a genie would pop out and hand him a world-class vaccine made by the University of Oxford which the French President and senior German officials would incorrectly cast doubt on, he'd bite your hand off," said Rob Ford, professor of politics at the University of Manchester. "Even better, the EU criticizes you for acting fast, only to fall far behind. Johnson couldn't have written this script himself."

Some European officials are baffled over why EU leaders would publicly bash a vaccine that the continent will rely on to put a stop to the pandemic. While they don't particularly care about perceptions of the EU in Britain, they are worried at any loss of confidence among EU citizens in the vaccine program and the implications for public health.

"The EU likes being the reasonable, sensible voice on the world stage. Criticizing the UK and the Oxford vaccine has made them look not in control. It was a huge error. The only explanation I can think of is that they panicked after Europe's rollout hadn't lived up to the hype," said a European diplomat based in Brussels.

"It would have been not only better for the vaccine rollout plan to know what we are actually dealing with, but better for our morale if they'd been more transparent from the start," said Mohammed Chahim, a Dutch member of European Parliament who sits on the public health committee. "Casting doubt on the efficacy of a vaccine and pointing fingers at the UK doesn't help anything."

Europe's vaccine mess, of course, is helpful for Johnson as he tries to move Britain into what he hopes will be the final phase of the pandemic.

"The cultural differences in bureaucracy are being laid bare for the public. The EU is obsessed with rules, is inflexible and struggles to adapt to events in real time. The UK has been better at that this time," says Ford. "The government screwed up large parts of the pandemic, but if the end of lockdown comes faster than the rest of Europe, that is probably what the public will remember -- a British success story."