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The Queen yesterday became Britain's oldest monarch, overtaking a record set by her great-great-grandmother, Queen Victoria, and royal commentators expect her to be on the throne for some time to come.
Victoria was born on May 24, 1819, and lived for 81 years, seven months and 29 days,
dying in 1901.
Elizabeth, the 40th monarch since William the Conqueror took the English throne in 1066, was born on April 21, 1926.
She eclipsed Victoria's record as the country's oldest sovereign at about 6am (NZ time) yesterday.
No special events were planned to mark the occasion, with officials saying the Queen would be working as normal, but commentators said it was an impressive milestone.
"Even allowing for the improvement in medicine since Victoria, it is remarkable," Peter Hennessy, professor of contemporary British History at the University of London's Queen Mary college, told the Daily Telegraph.
"I cannot think of any other head of an institution who has not put a foot wrong over such a long period of time."
The 81-year-old has seen her popularity restored after a difficult decade for the monarchy following the death of Princess Diana, ex-wife of Elizabeth's eldest son and heir-to-the-throne Prince Charles, in a 1997 Paris car crash.
Many Britons berated the royal family, feeling they had not shared enough in a public outpouring of grief, an atmosphere captured in last year's Oscar-winning film The Queen in which Elizabeth was portrayed as a dignified but misunderstood figure.
There are few calls nowadays for the abolition of the monarchy, although Republic, a pressure group that campaigns for an elected head of state, said it was time she retired.
"Elizabeth Windsor is now 81, well past the normal age for retirement. Over the next few years, question marks are going to be raised about her continuing ability to perform her official duties," said the group's spokesman Graham Smith.
"It would be in her interests and those of the country if she stepped down and enjoyed a peaceful retirement."
But the monarch, who would appear to have genes on her side, since her own mother died at 101, has shown no desire to step down from the role.
"Inevitably when somebody reaches a milestone like this, questions of future fitness arise," royal biographer Robert Lacey said, commenting that Prince Charles had begun taking on some of her duties.
But he said: "I don't think there's a slightest question of the Queen giving up or abdicating."
Elizabeth, who became the first reigning British monarch to celebrate a diamond wedding anniversary in November, still has some way to go if she is to beat Victoria's record as Britain's longest-reigning monarch.
She ruled for almost 64 years and Elizabeth will break this in September 2015.
While she remains on the throne, the position of the monarchy seems secure, but opinion polls suggest that Charles' accession could again raise question marks about its future.
"It is unacceptable for Charles to take over as head of state without a referendum on the future of this antiquated institution," Smith said.
"An early retirement by the Queen will open up that debate and allow Britain a free hand in reforming our creaking constitution."
- Reuters
