SANDRINGHAM, England (Reuters) - Britain’s Queen Elizabeth, 90, missed a traditional Christmas church service on Sunday for the first time in decades due to a heavy cold, a Buckingham Palace spokesman said.

Elizabeth, the world’s longest-reigning living monarch, and her husband Prince Philip, 95, suffering what the Palace described as heavy colds this week, delayed by a day the journey to their Sandringham country residence in eastern England. They traveled instead by helicopter on Thursday.

The queen has attended the Christmas service at the parish church of St Mary Magdalene in Sandringham every year since the family started celebrating Christmas there in 1988.

Before then, the family spent Christmas at Windsor where Elizabeth attended a service since the mid-1960s. It was unclear when Elizabeth last missed a Christmas Day service, if ever.

Philip was driven to church in Sandringham on Sunday and walked in unaided from a Range Rover, a Reuters photographer said, while Prince Charles, heir to the throne, walked to the church with his wife Camilla and other members of the family.

“The Queen continues to recover from a heavy cold and will stay indoors to assist with her recovery,” a Palace spokesman said. “Her Majesty will participate in the Royal Family Christmas celebrations during the day.”

Elizabeth’s other children, Anne, Andrew and Edward attended along with Prince Harry, Charles’s second son. Prince William, second-in-line to the throne, is spending Christmas with the parents of his wife, Kate.

After more than six decades on the throne, the Queen has cut back on international tours but still regularly performs official duties around Britain, although she said on Tuesday she would reduce such visits.

While Elizabeth’s father, George VI, died at the relatively young age of 56, her mother, who was known as Queen Elizabeth the Queen Mother, lived until 101 and was still appearing in public almost up until her death in 2002.

Both the Queen and Prince Philip’s good health has allowed them to remain very much in the public eye, despite their age. Elizabeth has maintained the popularity of the monarchy despite years of political, social and cultural change since she became Queen Elizabeth II on Feb. 6, 1952, aged just 25.

The Times reported on Wednesday that Philip carried out more public engagements last year than did his grandsons William and Harry, and William’s wife Kate combined.

(Writing by Guy Faulconbridge; Editing by Louise Ireland)