Only Queen Victoria -- whose relatives and descendants make up a who's who of European royalty across the 19th, 20th and 21st centuries -- spent more time on the throne.

The 85-year-old Elizabeth II, who acceded to the throne on February 6, 1952, has now ruled for 59 years and 95 days, more than every other monarch bar Victoria in more than 1,000 years of British history when leap-year days are included.

The longevity of her reign pushes George III, who was king from 1760 until 1820 during the period that the United States won independence from Britain, into third place.

George suffered from mental illness in the latter part of his life which was documented in the successful film "The Madness of King George."

Buckingham Palace said there would be no celebration to mark the occasion.

"It's business as usual," a spokesman said.

The queen, who celebrates her diamond jubilee next year, will become the longest reigning monarch in September. 2015.

Last month, Prince Charles, 62, broke the record for spending the longest time as heir-to-the-throne.