The Duke of Edinburgh has issued a rare public statement to praise key workers who are keeping essential services running during the coronavirus crisis.
Prince Philip, 98, also said he wanted to recognise the "vital and urgent" medical and scientific work taking place to tackle the pandemic.
He has rarely been seen in public since he retired from public duties in 2017.
During the outbreak the duke has been staying at Windsor Castle with the Queen, who turns 94 on Tuesday.
In his message, published online, the duke said: "As we approach World Immunisation Week, I wanted to recognise the vital and urgent work being done by so many to tackle the pandemic; by those in the medical and scientific professions, at universities and research institutions, all united in working to protect us from Covid-19.
"On behalf of those of us who remain safe and at home, I also wanted to thank all key workers who ensure the infrastructure of our life continues; the staff and volunteers working in food production and distribution, those keeping postal and delivery services going, and those ensuring the rubbish continues to be collected."
The duke is affiliated to more than 750 organisations, including those in the scientific, technological research, healthcare and infrastructure sectors which have been responding to the outbreak.
His grandson, the Duke of Cambridge, said on Friday that the Royal Family were doing everything they could to protect the duke - who turns 99 in June - and the Queen.
Prince William said: "Obviously I think very carefully about my grandparents who are the age they're at - we're doing everything we can to make sure that they're isolated away and protected from this."
Earlier this month the Queen, who has cancelled her birthday gun salutes on Tuesday, made a televised address to the nation in which she stressed the country would overcome the virus.