King Charles has used his Christmas address to thank doctors and nurses who provided “strength, care and comfort” during his cancer treatment.

He also praised diversity and the way communities in the UK resisted summer riots after the murder of three children in Southport.

Speaking from Fritzrovia Chapel in London, a former sacred space of the demolished Middlesex hospital, the king offered his “heartfelt thanks” to the medical teams who supported him and his family “through the uncertainties and anxieties of illness”.

His remarks come as the Princess of Wales makes a gradual return to public duties after completing a course of chemotherapy. Kate said in September she was doing what she could to “stay cancer free”.

The king’s treatment for cancer is expected to continue in the new year almost a year after it was announced he was being treated for cancer. Further details about the condition of Kate and the king have not been disclosed.

The monarch said in his address: “I am deeply grateful, too, to all those who have offered us their own kind words of sympathy and encouragement.”

A substantial part of the king’s Christmas speech focused on the counter response to the violent aftermath of the fatal stabbings of three girls at a dance class in Southport on 29 July. He spoke of his “pride” at the way communities came together after the subsequent riots.

Serious disorder broke out triggered by false information about the alleged identity of the attacker. The disturbances, in which mosques and hotels housing asylum seekers targeted, were denounced as “far-right thuggery” by the prime minister, Keir Starmer. The king was kept updated daily at the time on the public disorder.

The violence abated only after a series of peaceful counter-protests and a swift police and judicial crackdown on the rioters. The king said: “I felt a deep sense of pride here in the United Kingdom when, in response to anger and lawlessness in several towns this summer, communities came together, not to repeat these behaviours, but to repair.”

He added: “To repair not just buildings, but relationships. And, most importantly, to repair trust; by listening and, through understanding, deciding how to act for the good of all.”

During the broadcast of the Christmas address, footage was shown of the king talking to emergency workers who responded to the fatal Southport stabbings.

The riots prompted widespread alarm and a prediction from the influential US billionaire Elon Musk on his X platform that “civil war is inevitable”.

Last week the king and Queen Camilla visited Waltham Forest town hall in north-east London to celebrate the community cohesion shown by Walthamstow residents, who took to the streets in August to stage one of the biggest peaceful counter-protests.

Charles suggested in his speech such community cohesion was also apparent on his visit to the South Pacific where he attended the Commonwealth summit in October. He said the trip was a reminder of “how diversity of culture, ethnicity and faith provides strength, not weakness”.

He added: “Across the Commonwealth, we are held together by a willingness to listen to each other, to learn from one another and to find just how much we have in common. Because, through listening, we learn to respect our differences, to defeat prejudice, and to open up new possibilities.”

The king also made reference to the “devastating effects of conflict in the Middle East, in central Europe, in Africa and elsewhere”. He also praised “humanitarian organisations working tirelessly to bring vital relief.”

He added: “The example that Jesus gave is timeless and universal. It is to enter the world of those who suffer, to make a difference to their lives and so bring hope where there is despair.”

The broadcast, produced this year by Sky News, ended with the London-based youth choir Inner Voices singing the carol Once in Royal David’s City.

The king attended the traditional Christmas Day church service at Sandringham alongside other royals but not his brother Prince Andrew.

It was announced last week that the Duke of York would not be attending the service amid controversy over his links with an alleged Chinese spy. He said to be preparing to spend Christmas Day with his ex-wife Sarah, the Duchess of York, this year.

The king and queen were joined at the Sandringham church by the Prince and Princess of Wales and their children, Prince George, 11, Princess Charlotte, nine, and Prince Louis, six. Also at the church were the Princess Royal and the Duke and Duchess of Edinburgh.