Rock of strength: Cameron hails Queen Elizabeth II on her 90th birthday
David Cameron led tributes Thursday in the House of Commons to Queen Elizabeth II and her 'unshakable sense of duty,'
Windsor: Queen Elizabeth II — Britain's oldest and longest-serving monarch — was celebrating her 90th birthday Thursday with a day at home and a short walk.
Her government and subjects are having gun salutes, fireworks and tributes in Parliament in her honour, and televised retrospectives are being broadcast of a royal life that has stretched from the Roaring '20s to the Internet age.
The queen was born Princess Elizabeth on 21 April, 1926, and became queen at 25 upon the death of her father, King George VI, in 1952. A majority of Britons have lived under no other monarch.
British Prime Minister David Cameron said the queen "has lived through some extraordinary times," from World War II to the moon landing, the end of the Cold War and the advent of peace in Northern Ireland.
Cameron led tributes Thursday in the House of Commons to the monarch and her "unshakable sense of duty," pointing out that the queen had provided counsel to 12 British prime ministers and met a quarter of all the US presidents in history.
"Her Majesty has been steadfast — a rock of strength for our nation, for our Commonwealth and on many occasions for the whole world," he declared.
At dusk, the Parliament building will be lit up in the red, white and blue of the Union Jack.
The queen is spending the day at Windsor Castle and will greet well-wishers on a walk through the town west of London. Hundreds have lined up hours beforehand, carrying cakes, cards, balloons and Union Jack flags.
"She's such an icon and a real role model for the children of today. And I think everybody should respect her for all the years that she's given for her country," said Donna Werner, an American tourist from New Fairfield, Connecticut. "I wanted to honour that by coming over here and being able to wave and show some love."
Elsewhere, the day was being marked with an eruption of pomp. Artillery companies will fire gun salutes from Hyde Park and the Tower of London, while the bells of Westminster Abbey will ring out in celebration. Later, the queen will light the first in a chain of 1,000 beacons to blaze across Britain and around the world.
Buckingham Palace has issued three portraits by photographer Annie Leibovitz to mark the day. One shows the queen surrounded by seven young grandchildren and great-grandchildren. The queen cradles 11-month-old Princess Charlotte in her lap, while Mia Tindall — 2-year-old daughter of the queen's granddaughter Zara Phillips and her husband Mike Tindal— stands clutching the monarch's black handbag.
Another shows the queen with Princess Anne, her only daughter. The third shows her on the steps of Windsor Castle with four of her beloved dogs: corgis Willow and Holly and dorgis (corgi-dachshund crossbreeds) Vulcan and Candy.
The queen will receive more birthday greetings on Friday, when she hosts U.S. President Barack Obama and his wife Michelle Obama for lunch at Windsor Castle.
But not everyone in Britain was succumbing to royal-mania. The anti-monarchist group Republic published a resolutely undeferential message headed "Happy Birthday Mrs. Windsor."
"A long life is no reason for a long reign," it said.