She began what is likely to be a busy programme of engagements in the run-up to her Platinum Jubilee year by meeting soldiers from the Royal Regiment of Canadian Artillery, some of whom are on guard duty at Buckingham Palace and Windsor. On the parade ground the Queen, who is Captain General of the regiment, presented the unit with the Captain General’s Sword.

       It will be given annually to reward exemplary leadership.

       Earlier, in between hours of going through official state papers in red boxes, the hardworking monarch, 95, held virtual audiences with the new Greek ambassador to Britain, Ioannis Raptakis, and Belize’s High Commissioner, Therese Rath.

       The meetings came after she issued a signed message praising and thanking those working in engineering and technology for their countless “invaluable” inventions.

       This year marks the 150th anniversary of the Institution of Engineering and Technology, of which she is patron.