Nonagenarian Margaret Keenan became the first citizen of the United Kingdom to be inoculated against the Covid-19 illness outside of a clinical trial. She was the first beneficiary of the UK's mass vaccination programme which began on December 8, days after the vaccine developed by Pfizer and BioNTech was given emergency use approval by authorities. Prime Minister Boris Johnson reacted to the development, expressing happiness but also issuing a warning. While calling the beginning of the immunisation programme a 'tremendous shot in the arm' for the country, he said that people shouldn't 'relax' when it comes to basic precautions. Watch the full video for more.