Thousands of Britons received the world’s first approved coronavirus vaccine on Tuesday as the UK embarked on a mass immunisation campaign without parallel in the country’s history.

But even as a 90-year-old grandmother and an 81-year-old named William Shakespeare became the inaugural recipients of the Pfizer/BioNTech vaccine outside clinical trials, the practicalities of rolling it out to 25m people judged at highest risk from the disease raised questions about how quickly the nation’s vulnerable population could be protected.

Matt Hancock, the health secretary, told lawmakers the arrival of the vaccine meant the end was in sight “not just of this terrible pandemic but of the onerous restrictions that have made this year so hard for so many”.