King Charles has delivered a personal message of gratitude to health workers who have supported him during his cancer treatment, in his annual Christmas speech.

In a candid message, he offered his “heartfelt thanks” to the doctors and nurses who helped with the “uncertainties and anxieties of illness”.

The King also praised the efforts of those building links between different communities in what he called the “anger and lawlessness” of the summer riots.

Diversity in ethnicity and faith is a sign of “strength, not weakness”, said the King’s message.

This year’s Christmas broadcast was delivered in the Fitzrovia Chapel in London, the first time a venue outside a royal residence had been used for over a decade.

It had been the former chapel of the Middlesex Hospital, reflecting the theme of paying respect to those working in the health services.

“All of us go through some form of suffering at some stage in our life, be it mental or physical,” said the King, but the “measure of our civilisation” is how people are supported at such moments.

The King’s message, recorded earlier this month, expressed his gratitude for “selfless” medical professionals and volunteers who used their skills to “care for others – often at some cost to themselves”.

He acknowledged the help for others in his family, with the Princess of Wales receiving a cancer diagnosis this year.

And he thanked the public for their kind words and messages, after his own cancer diagnosis was revealed in February.

The broadcast showed him meeting cancer patients, when he returned to public engagements in April, during a visit to University College London Hospital.

The King’s treatment will continue into 2025, but as a positive sign of progress, he is planning a busy schedule of visits and overseas trips next year.

Another major theme of the speech was a focus on community cohesion.

The King praised the efforts of those who had sought to build bridges between communities after the summer riots, that had followed the knife attack in Southport.

“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. To repair not just buildings, but relationships,” said the King.

“Diversity of culture, ethnicity and faith provides strength, not weakness,” said the King, who praised efforts to “respect our differences, to defeat prejudice”.

The King’s words echo the Christmas message given by his mother the late Queen Elizabeth in 2004, when she addressed community tensions, saying “diversity is indeed a strength and not a threat”.

In a speech earlier this year on Commonwealth Day, the King had also stressed the same message that “diversity is our greatest strength”.

The Christmas broadcast included pictures of Prince William and Catherine thanking emergency workers who responded to the Southport knife attack, in a visit which had included a meeting with bereaved families.

Accompanying the speech a community choir sang the carol Once in Royal David’s City. And a Christmas tree seen in the broadcast has since been donated to a hospice in Clapham.

There were words of sympathy from the King for those at risk in wars around the world, with conflicts in Ukraine and the Middle East.

The King commended the “remarkable veterans of that very special generation” as he recalled the 80th anniversary commemorations of the D-Day landings.

The broadcast followed the convention of showing working royals, so there were no sightings of either Prince Harry or Prince Andrew.

King Charles is spending Christmas Day in Sandringham in Norfolk.

Crowds gathered in the morning to watch him going to a church service with his family, including Queen Camilla and the Prince and Princess of Wales.