King Charles has praised the work of volunteers, calling them a “selfless army of people” who form an “essential backbone of our society”.

In his second Christmas speech, the king said he was delighted that hundreds of volunteers and their representatives attended his coronation in May, saying their presence “emphasised the meaning of coronation itself, above all, a call to us all to serve one another, to love and care for all”.

In an apparent reference to rising homelessness, and people housing displaced victims of conflicts, such as Ukrainians, the monarch highlighted one part of the story of Jesus when “Mary and Joseph were offered shelter in their hour of need by strangers”.

Last Christmas he had underlined the cost of living crisis and the “great anxiety and hardship” of many struggling to “pay their bills and keep their families fed and warm”.

In November, he launched the Coronation Food Project, which will distribute otherwise wasted food to people struck by food poverty. In Monday’s speech, he said “we need to build on existing ways to support others less fortunate than ourselves”.

This month he said the world remained “dreadfully far off track” in key climate targets arising from the 2015 Paris agreement and called for “meaningful change” in his opening statement at the Cop28 climate summit.

Standing in front of a replantable Christmas tree for his 25 December broadcast this year the king said the planet had to be protected “for the sake of our children’s children”.

He added: “During my lifetime I have been so pleased to see a growing awareness of how we must protect the Earth and our natural world as the one home which we all share.”

He also referenced the wars in Gaza and Ukraine, saying: “At a time of increasingly tragic conflict around the world, I pray that we can also do all in our power to protect each other.”

The king recognised other faiths, describing how “great religions of the world” celebrated festivals with a special meal, and how it was the responsibility of “people of all faiths and of none” to care for the natural world.

The speech was delivered in Buckingham Palace’s centre room, which opens on to the balcony that overlooks the Mall.

Earlier in the day the royal family attended the traditional Christmas day church service at the Sandringham estate.

Royal fans gathered as the Prince and Princess of Wales walked hand in hand with their children, George, Charlotte and Louis, behind the king and queen, who were greeted by about 1,000 local residents, many of whom had waited hours outside the estate on Christmas morning.

Sarah, Duchess of York – the former wife of the disgraced Duke of York – joined the service in what appeared to be a public show of her return to the heart of the family.