Queen Elizabeth II waves to the crowd with Prince Philip appearing in good health as they arrive on the first day of the Royal Ascot horse race meeting on June 20. Photo / AP
Prince Philip has been admitted to hospital as a "precautionary measure" for treatment of an infection arising from a pre-existing condition, Buckingham Palace says.
Philip was supposed to be accompanying the Queen to the State Opening of Parliament on Wednesday but his place was taken by Prince Charles.
Prince Philip is understood to have been taken to hospital by car from Windsor to London on Tuesday evening, as a precautionary measure on the advice of his doctor. He has been out of bed today, and is said to be in good spirits.
A Buckingham Palace spokesman said: "The Duke of Edinburgh was admitted to King Edward VII Hospital in London last night, as a precautionary measure, for treatment of an infection arising from a pre-existing condition.
He recently said he was stepping down from public events.
On May 4, staff from all royal residences across the UK were summoned to a meeting at Buckingham Palace, in a move billed as "highly unusual" by royal watchers and leading to speculation there had been a death.
However the announcement was made that Prince Philip would be stepping down from public engagements.
"In taking this decision, the Duke has the full support of the Queen. Prince Philip will attend previously scheduled engagements between now and August, both individually and accompanying the Queen," the statement at the time read.
"Thereafter, the Duke will not be accepting new invitations for visits and engagements, although he may still choose to attend certain public events from time to time.
"The Duke of Edinburgh is Patron, President or a member of over 780 organisations, with which he will continue to be associated, although he will no longer play an active role by attending engagements.
"Her Majesty will continue to carry out a full program of official engagements with the support of members of the Royal Family."
Just yesterday, Prince Philip attended Royal Ascot, accompanying the Queen for a full day of activity in hot temperatures.
On Saturday, he appeared at Trooping the Colour, appearing in good spirits for the carriage ride and with his family on the Buckingham Palace balcony.
Meanwhile, Queen Elizabeth is outlining the British government's legislative programme in parliament, carrying on with royal duties despite the announcement that her husband has been hospitalised.
Prince Philip's rare absence from the State Opening of Parliament adds to the solemnity of an occasion where Prime Minister Theresa May is presenting a legislative programme trimmed down following the loss of her majority.
While the Queen reads the Queen's Speech to lawmakers, it is written by the prime minister and her staff.
May, who called a snap election expecting to fatten her party's majority, is promising her minority government will be one "that consults and listens."
The speech was delivered with less pageantry than normal a result of the timing of the snap election.
The Queen arrived at Parliament in a car, rather than a horse-drawn carriage, and delivered the speech in everyday dress, instead of the traditional royal robes.
Despite news of his retirement in May, Prince Philip has seemed in good health following several years of minor illness.
In June 2013, he had an exploratory operation on his abdomen which was said to have gone "as planned".
He also suffered a serious health scare over Christmas 2011, which he spent in hospital for treatment for a blocked coronary artery.
He underwent a "minimally invasive procedure" of coronary stenting to unblock it, which was declared a success and was discharged four days later.
Later the same year, during the Queen's Diamond Jubilee celebrations, he was admitted to hospital with a bladder infection, spending five days on a ward and missing the final part of the jubilee festivities.
In 2016, however, he carried out official meetings and visits on 110 days of the year, remaining patron or president of around 800 organisations and taking an active interest in his Duke of Edinburgh Award scheme.