The King was presented with a home-made birthday card by a group of schoolchildren who sang Happy Birthday as he visited a surplus food project.

Charles shared his 76th birthday with the first anniversary of the Coronation Food Project, which raised £15 million to open the first two Coronation Food Hubs in Deptford in south-east London and Knowsley in Merseyside.

The smiling King appeared on good form as he arrived at the Deptford Trading Estate for the hub’s official opening on Thursday, without the Queen, who is recovering from a chest infection.

Volunteers from the Felix Project, who were dressed in the charity’s signature green and who will run the London hub, clapped, cheered and waved flags as Charles stepped from his Bentley.

He gave a wide grin and waved at members of the public who had gathered to see him, before being greeted by London Mayor Sadiq Khan.

The King attended a “surplus food festival”, which showcased meals created from food that would otherwise have gone to waste.

And he sat down with a group of children from Peckham’s Rye Oak Primary School who will benefit from the new hub, and listened to them talk about the foods they like, asking about their school lunches.

Asked if he would be putting his feet up for his birthday, he said: “Not quite.”

At the end of the conversation, he said: “I hope you have a very happy Christmas.”

Charles is treating his birthday as a normal working day despite facing a difficult year in which both he and daughter-in-law the Princess of Wales were diagnosed with cancer.

His visit celebrated the first anniversary of his Coronation Food Project, which he launched last year in a bid to bridge the gap between food need and food waste in the UK amid the cost-of-living crisis.

He opened the second hub, in Knowsley, Merseyside, virtually, saying: “Please give my kindest wishes to everybody there.

“I hope it makes an enormous difference to all their remarkable work that they do.”

He then unveiled plaques for both hubs.

Afterwards one little girl left her seat to hand the King a birthday card, which had been signed by all the children, and they then broke into a well-rehearsed rendition of Happy Birthday.

Charles smiled and thanked them.

During his visit, he toured the facility, meeting representatives of food banks, schools and community groups, as well as beneficiaries.

He was shown a newly installed industrial freezer, which measures more than 48ft (14.8m) by almost 14ft (4.2m) and will increase the capacity to store frozen food by 400%.

There were also stalls showcasing food donated to the project by major retailers.

The Marks & Spencer stand was showcasing digestive biscuits which the company had donated.

The King said: “Are these very popular, I expect?

“We used to get them in the good old days of British Rail.”

He was accompanied on the tour of the facility by Mr Khan, Coronation Food Project chairwomen Dame Martina Milburn and Baroness Louise Casey, and other representatives of the charities involved in the project.

The Coronation Food Project hopes to open a further eight hubs in the future.

As he left, Charles was greeted by excited crowds who wished him a happy birthday, handing him flowers and cards.

The crowd cheered ‘hip hip hooray’ three times.

Members of the royal family also wished the King a happy birthday, with the Prince and Princess of Wales sharing a photo of a relaxed-looking Charles wearing sunglasses and a garland during his recent tour to Samoa.

William and Kate’s message read: “Wishing a very Happy Birthday to His Majesty The King!”

The monarchy’s official social media accounts posted a message alongside a more formal portrait of the King standing in the White Drawing Room at Buckingham Palace.

Gun salutes were fired in Green Park by The King’s Troop Royal Horse Artillery and at the Tower of London by the Honourable Artillery Company as part of the military’s traditional celebrations on the sovereign’s birthday, and bells rang out at Westminster Abbey where the King was crowned in 2023.

On the even of his birthday, Charles had walked the red carpet at the global premiere of Gladiator II, meeting stars Denzel Washington, Paul Mescal and Pedro Pascal.