The Prince of Wales made a plea for "togetherness" as the Royal family united for a Westminster Abbey carol concert in the face of escalating public criticism from the Duke and Duchess of Sussex.

The Prince spoke hours after the Duke of Sussex launched his most explicit and direct accusations about his brother to date, alleging in a Netflix documentary that he had broken a pledge never to let the "institution" come between them.

Prince Harry claimed that the palace had "lied" to protect his older brother, and accused his father of saying "things that just simply weren’t true" during negotiations for the Sussexes to leave the working Royal family.

Buckingham Palace and Kensington Palace have declined to comment on the string of allegations against members of the Royal family and staff.

On Thursday evening, the King, Queen Consort, Prince and Princess of Wales, and the wider family assembled at Westminster Abbey in an unmistakable show of unity intended to demonstrate their focus.

Prince George and Princess Charlotte joined their parents for the Together at Christmas carol concert, coordinating festive burgundy and cream outfits with their royal relatives.

The family was greeted by cheers from the public, including shouts of "Kate, we love you" and "Prince William, we love you".

During the service, which was arranged by the Princess of Wales for 2,000 worthy members of the public, the Prince spoke of how Jesus "inspired people to commit themselves to the best interests of others" with a mission to "serve, not be served".

Quoting from Queen Elizabeth II's Christmas Speech from 2012, Prince William said: "At Christmas, I am always struck by how the spirit of togetherness lies also at the heart of the Christmas story."

The concert was held to recognise the "selfless efforts of individuals, families and communities across the UK, and celebrate and showcase the joy that human connection and togetherness can bring".

Kensington Palace said the event was dedicated to the late Queen Elizabeth II and the values she demonstrated, including "duty, empathy, faith, service, kindness, compassion and support for others".

The palace said these principles were "shared and personified by the inspirational guests who have been invited to the abbey in recognition of their tireless work to help and care for those around them".

A Christmas tree in the abbey was decorated with small Paddington Bear decorations, a nod to the late Queen’s famous sketch, while guests were greeted with atmospheric snowflakes from a snow machine as they arrived at the entrance.

Among guests were the Countess of Wessex, the Duke and Duchess of Gloucester, the Duke of Kent, Princess Alexandra, Princess Beatrice and Eugenie and their husbands, Prince and Princess Michael of Kent, and Zara and Mike Tindall, as well as the Middleton family.

Other guests taking part in the service included Hugh Bonneville, the actor who starred in Paddington, and Melanie C, the singer.

Royal sources have repeatedly emphasised that neither he, nor other members of the Royal family, would be watching Harry & Meghan, which spelled out the Duke and Duchess of Sussex’s grievances against the palace, press and their relatives.

In the documentary, the Duke said he and his wife would "never get genuine accountability or a genuine apology" for the way they were treated by the Royal family.

He claimed that his brother and father "were very much focused on the same misinterpretation of the whole situation", even during "hard" conversations close to the Duke of Edinburgh’s funeral.

He also accused the palace of "institutional gaslighting" and lying about a joint statement issued in 2020 denying a report of Prince William "bullying us out of the family".

"I couldn't believe it," he said. "No one had asked me permission to put my name to a statement like that."

"Within four hours [of a newspaper report making the claims] they were happy to lie to protect my brother and yet for three years they were never willing to tell the truth to protect us," he said.

He also accused the palace of trading stories with the "tabloids" to protect some members of the family with negative leaks about others.

"William and I both saw what happened in our dad [King Charles III]'s office, and we made an agreement that we would never let that happen to our office," he said.

"To see my brother's office copy the very same thing that we promised the two of us would never, ever do, that was heartbreaking."

He added that the "saddest part of it was this wedge created between myself and my brother", with the Prince of Wales "now on the institution’s side".

Of the Sandringham Summit, in which the family finalised details for the Sussexes’ departure from working royal life, the Duke said: "It was terrifying to have my brother scream and shout at me and my father say things that just simply weren’t true.

"And my grandmother [the late Queen] quietly sit there and take it all in."