Queen Elizabeth Has Sprained Back and Misses Public Ceremony with 'Great Regret'

Queen Elizabeth has had another setback in her return to public duties.

She has sprained her back and with "great regret" missed the solemn Remembrance Day ceremony in London on Sunday.

It was to have been the 95-year-old monarch's returned to public view for the first time in two weeks since she was asked to rest by medics.

In a short message, Buckingham Palace announced early on Sunday, "The Queen, having sprained her back, has decided this morning with great regret that she will not be able to attend today's Remembrance Sunday Service at the Cenotaph. Her Majesty is disappointed that she will miss the service."

The Queen is said by a royal source to be "deeply disappointed," as she regards the moving ceremony as "one of the most significant engagements of the year."

It's unknown how the Queen suffered the injury but it is likely to have happened in the last day or so, as on Thursday the palace had said she intended to be at the ceremony. And it is unrelated to her doctor's recent advice to rest, PEOPLE understands.

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"Nobody regrets the Queen's absence today more deeply than Her Majesty," the source adds.

Many people were looking ahead to seeing her on the balcony of the Foreign and Commonwealth Office, above the memorial to Britain's war dead. But, it would have been difficult for her to travel the 30 miles by car to London from Windsor and also meet military and political leaders and stand on the balcony for about 30 minutes while coping with a sprained back.

She is hoping to be able to continue as planned with her schedule of light official duties that she has been undertaking at home at Windsor, in the coming week.

As was originally planned, her wreath was placed at the memorial on her behalf by her son and heir, Prince Charles. Charles, who turned 73 on Sunday, also laid a wreath of his own, decorated with white Prince of Wales feathers. His wife Camilla, 74, had put the finishing touches to the wreath a few days ago.

The Queen's place on the balcony above the Cenotaph was taken by her cousin, the Duke of Kent, who was accompanied by another of Her Majesty's cousins, Princess Alexandra. On a neighboring balcony stood Kate Middleton who was flanked on her right by Camilla, Duchess of Cornwall and Sophie, Countess of Wessex, on her left as tributes were paid to those who had been lost in the two world wars and conflicts since.

Prince William, watched by his wife the Duchess of Cambridge, and dressed in the uniform of a Squadron Leader of the Royal Air Force, stepped forward after his father to lay a wreath of his own.

Moments earlier, the royals had emerged from the Foreign Office onto Whitehall, to stand in tribute for the two-minute silence that was prefaced by a ringing of the Big Ben bell at the Houses of Parliament, a stone's throw away, and ended by the sound of a gun salute from nearby Horseguards Parade. As hundreds of veterans stood in silent contemplation, Prince Charles appeared reflective, his eyes heavy, while a couple of yards away, Prince William was solemn and deep in thought.

Also among the royal party paying their respects were Princess Anne and Prince Edward. Prime Minister Boris Johnson led the politicians, including past Prime Ministers, while representatives of neighboring counties and the 54 nations of the Commonwealth and the leaders of the various branches of the military also laid wreaths.

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The ceremony ended after about 25 minutes with a stirring rendition of the national anthem, God Save The Queen.

Remembrance Sunday is one of the most sacred events in the Queen's calendar, and she has only missed a handful during her 69-year reign, such as when she was pregnant or out of the country on a tour.

When the palace announced on Thursday that she was set to attend the Cenotaph ceremony, a statement added she would not be attending a planned engagement, at the General Synod of the Church of England (Prince Edward "will attend as planned," the palace said in a statement).

It follows a period of concern about her health since she pulled out of trip to Northern Ireland on Oct. 19 and stayed overnight in King Edward VII hospital in London for some "preliminary investigations."

Charles allayed some of those concerns when he answered well-wishers questions during a visit to Brixton, South London, on Thursday, telling someone who asked from the crowd "She's alright, thank you."

The Queen spent last weekend at Sandringham, her country home in Norfolk, most likely checking on her horses as she was spotted with her racing manager John Warren. Back at Windsor, she has been carrying out "light duties" such as video calls and audiences, via telephone, with PrIme Minister Johnson.