Landmark day as Queen Elizabeth goes about her business

Queen Elizabeth, Britain's longest-serving monarch, will spend her 90th birthday today much as she does every other day, unveiling a plaque, doing a walkabout and hearing praise from her subjects.

Prime minister David Cameron will lead the tributes with a "humble address" in the House of Commons and Labour leader Jeremy Corbyn, a lifelong republican, will follow up with an encomium of his own.

“Tomorrow is an important landmark not only for her majesty the queen but also for our country and the Commonwealth as a whole,” Mr Cameron told MPs on Wednesday.

“She has served our nation with such dignity and such ability for so many years – 64 years on the throne. And I think it’s right we’re going to have the opportunity in the house tomorrow to pay tribute to what she has done and I know the whole country and the whole house will want to join me in saying long may she reign over us.”

The queen will start her day by unveiling a plaque marking the start of a four-mile queen's walkway at the foot of Castle Hill in Windsor. The walkway connects 63 points of interest in the town, one for each year the queen was on the throne when she surpassed Queen Victoria last year to become the longest-reigning monarch in British history.

In London, there will be a 41-gun salute in Hyde Park and a 62-gun salute at the Tower of London and when dusk falls, the river frontage of the Houses of Parliament will be illuminated in red, white and blue.

Later in the evening, the queen, accompanied by Prince Philip, who will turn 95 in June, Prince Charles and Camilla, will light the first in a chain of 1,000 beacons across the country and around the world to celebrate her birthday.

Official birthday

Today is not even her official birthday, which comes in June and will see the traditional Trooping the Colour on Horse Guards Parade. There will be a service of thanksgiving at St Paul’s Cathedral and the pubs will be allowed to stay open late.

In between, in the middle of May, there will be an open air concert in the grounds of Windsor Castle, featuring Kylie Minogue, Andrea Bocelli and James Blunt.

The queen can enjoy her birthday in the knowledge that the monarchy is more popular than ever in Britain, with 68 per cent of the public believing the institution to be good for the country, according to a YouGov poll last year, compared to just 9 per cent who think it’s bad for Britain.

The majority of voters of all political parties and every age group support the monarchy, although older people are most enthusiastic, with almost eight in 10 over-60s saying the monarchy is good for Britain.

Seven out of 10 Britons believe the monarchy should continue and more than six in 10 believe it will still be around in 100 years.

The popularity of the British monarchy is not unique in Europe, with the Danish queen polling as well as Queen Elizabeth and the King of Norway enjoying an astonishing 93 per cent approval rating.

Longevity

The institution’s resilience in Britain owes much to the longevity of the queen, whose reign has seen 12 prime ministers, starting with

Winston Churchill

.

Reserved sometimes to the point of remoteness, she has nonetheless remained popular through more than six decades, only dipping in public esteem during the 1990s, in the years before and after the death of Diana, Princess of Wales.

In 1992, the year she called her “annus horribilis”, the marriages of tree of her four children – Charles, Anne and Andrew – collapsed, giving the impression to some that hers was a dysfunctional family.

When Diana died in a Paris car crash five years later, the queen misread the public mood, staying in Balmoral at first instead of joining the grieving crowds in London.

Since then, the queen's image has been restored and that of Prince Charles and Camilla have improved. Despite tabloid accusations that he is "work-shy", Prince William and his wife Kate Middleton remain popular.

William this week described the queen as the best role model he could have, hinting that he will follow her example rather than that of his father.

“The queen’s duty and her service, her tolerance, her commitment to others – I think that’s all been incredibly important to me and it’s been a real guiding example of just what a good monarch could be,” he said.