As of Saturday, the Queen will have outlived her great-great grandmother, Queen Victoria, who died on Jan 22, 1901 at the age of 81 years, seven months, four weeks and one day, the Telegraph reported.

Queen Elizabeth II, who will be 82 on April 21, plans to spend the day at Windsor Castle with the Duke of Edinburgh.

There will be no public pronouncements or fanfare to mark the milestone, the newspaper said.

"Even allowing for the improvement in medicine since Victoria, it is remarkable," British historian Peter Hennessy told the 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. In those years she has presided over the most dignified withdrawal from the superpower status, which is no bad legacy. The way she has adapted, without succumbing to faddish fashions, is a gift of genius."

The country's longest-serving male monarch was George III, who was 81 years and 239 days old when he died in 1820.