Prince Andrew leads the pack at King Constantine of Greece’s memorial service: Duke of York grins as he greets royal guests and takes them to their seats in rare public appearance alongside ex-wife Fergie

Prince Andrew was seen leading members of the Royal Family at a service of thanksgiving at Windsor Castle for the late King Constantine of Greece.

King Charles III missed the service as his treatment for cancer continues, while Prince William had been due to give a reading but pulled out for ‘personal reasons’.

The Prince of Wales is understood to have called the family to apologise, while Kensington Palace confirmed the Princess was ‘doing well’ as she recovers at home. 

But the Duke of York was pictured leading the pack in a rare public appearance as mourners arrived for the service.

Filing behind Prince Andrew was Sarah, the Duchess of York, followed by Vice Admiral Timothy Laurence, Zara and Mike Tindall, and Princess Anne.

Although other major royals were absent, Prince Andrew was joined by Queen Camilla, who  appeared to grin as she arrived at the Castle this morning, and was greeted at the door.

She smiled warmly at those gathered to meet her, before entering the venue and adopting a solemn and dignified silence.

They will be joined by the late king’s widow Queen Anne-Marie, their eldest son, Crown Prince Pavlos and other members of the Greek royal family for the service in the nave of the 15th century chapel.

Prince Andrew was present along with Sarah, Duchess of York and his daughters Princess Eugenie and Beatrice because it was deemed a personal family event.

It is also understood that the Duke of York was attending the service as a member of the British Royal Family and had been invited by the Greek Royal Family.

King Charles was at Windsor Castle earlier in the day but left before the service began – with the reception afterwards set to be hosted by Camilla.

Charles was unable to attend Constantine’s funeral in Athens last year because of commitments which included meeting the president of Cyprus. The Princess Royal represented him at the service.

Camilla’s role in the service will see her again taking the reigns as she works to take the pressure off her husband.

Members of the Royal family have rallied around the King, with Prince William returning to duties after spending time caring for his wife Princess Kate.

Charles’ profound sense of duty and strong work ethic has seen him continue working privately through treatment.

Today’s service at St George’s Chapel was held in honour of the King’s close friend and second cousin Constantine II, the former ruler and last king of Greece.

The King has reportedly sought spiritual advice from his friend Archimandrite Ephraim, Abbot of the Greek Orthodox Vatopedi monastery on Mount Athos.

Abbot Ephraim is said to have told Greek media outlets: ‘Yes, he has been in contact since the diagnosis and I believe he’ll overcome it. Charles has a spiritual sophistication, a spiritual life.’

Charles, 75, who was diagnosed with an undisclosed form of cancer just over a fortnight ago, is not carrying out public duties while he has treatment.

Constantine was a first cousin once removed and sailing partner of the late Duke of Edinburgh, and died at the age of 82 in January last year, decades after being toppled from the throne in a military coup.

The King had a close friendship with Constantine, choosing him as a godfather for his son William, now the Prince of Wales.

The former king was also godfather to the daughter of Prince and Princess of Michael of Kent, Lady Gabriella Kingston.

Constantine, who died in an Athens hospital, acceded to the throne at the age of 23 in 1964.

The young king, who had won Olympic gold in sailing, was initially hugely popular.

By the following year he had squandered much of that support with his active involvement in the machinations that brought down the popularly elected Centre Union government of prime minister George Papandreou.

The episode, still widely known in Greece as the ‘apostasy’ or defection from the ruling party of several politicians, destabilised the constitutional order and led to a military coup in 1967.

Constantine eventually clashed with the military rulers and was forced into exile.

The dictatorship abolished the monarchy in 1973 and a referendum after democracy was restored in 1974 dashed any hopes Constantine had of reigning again.

He lived in exile for many years in Hampstead Garden Suburb in north London, before returning to his home country in 2013.