Duchess of Cambridge gives birth to baby boy After a day in which the nation had waited expectantly for news, the couple decided to delay the announcement of the birth for four hours because "they wanted to spend a bit of time with their baby first, and needed to make the necessary phone calls to the Queen and other members of their families," an aide said. Everyone is absolutely delighted. It's been a wonderful day," the aide added. The news finally came at 8.29pm, with the formal announcement that "The Duchess of Cambridge has been delivered of a son." Crowds cheer outside Buckingham Palace (REUTERS) It was greeted by loud cheers outside the Lindo wing of St Mary's hospital in Paddington, where hundreds of members of the public had gathered, sensing a historic moment might be imminent. A spokesman for the Duke and Duchess said that all the members of the Royal family were "absolutely delighted" at the news. David Cameron declared the birth "an important moment in the life of our nation." Speaking outside 10 Downing Street, the Prime Minister said: "It is wonderful news from St Mary's, Paddington, and I am sure that right across the country, and indeed right across the Commonwealth, people will be celebrating and wishing the royal couple well. It is an important moment in the life of our nation but, I suppose, above all it is a wonderful moment for a warm and loving couple who have got a brand new baby boy. It has been a remarkable few years for our royal family: a royal wedding that captured people's hearts, that extraordinary and magnificent Jubilee and now this royal birth, all from a family that has given this nation so much incredible service. They can know that a proud nation is celebrating with a very proud and happy couple tonight. The Duchess, who had been admitted to the hospital at 5.30am when she was already in the "early stages" of labour, gave birth naturally, under the supervision of the Queen's former gynaecologist Marcus Setchell. Mr Setchell later left the hospital, saying: "Wonderful baby, beautiful baby." Guy Thorpe-Beeston, a consultant obstetrician at the hospital, and Dr Sunit Godambe, consultant neonatologist at St Mary's, were also present at the birth. The Queen's gynaecologist, Alan Farthing, was not present. The baby, who will be called Prince (his Christian name) of Cambridge, replaces Prince Harry as the third in line to the throne. It is the first time for more than 100 years that three direct heirs to the throne have been alive at the same time. The Prince of Wales said in a statement: "Both my wife and I are overjoyed at the arrival of my first grandchild. It is an incredibly special moment for William and Catherine and we are so thrilled for them on the birth of their baby boy. Grandparenthood is a unique moment in anyone's life, as countless kind people have told me in recent months, so I am enormously proud and happy to be a grandfather for the first time and we are eagerly looking forward to seeing the baby in the near future. Kensington Palace decided at the last minute to issue a press release to the media before a bulletin bearing the baby's details had left St Mary's Hospital. Minutes later, the Duke's press secretary, Ed Perkins, emerged from the front door of the Lindo Wing carrying a red leather folder with the baby's details on a piece of paper inside, which he handed to an orderly in a waiting Jaguar to be driven to Buckingham Palace. The bulletin was then driven to Buckingham Palace where it was placed on an easel - previously used to announce Prince William's birth in 1982 - within view of hundreds of people who had waited there all day hoping to be first with the news. The baby's sex means that Britain is likely to be ruled by kings for 80 years or more when Prince Charles succeeds the Queen. It also means that changes in the rules of succession, agreed by Parliament and the Commonwealth nations to give girls parity with boys, may not be needed for another generation. Early this morning, the Duchess and the Duke had managed to give the world's media the slip when they were driven from Kensington Palace to the hospital in a Ford Galaxy people carrier, going in through a back entrance also used by Diana, Princess of Wales, when Prince William was born. After going in through the Mary Stanford wing, one of the public areas of the NHS hospital, the couple were taken to the private Lindo wing, where the Duchess had chosen to give birth. Kensington Palace declined to say whether the Duchess, who was up to a week overdue, had been induced or had begun labour naturally. Her royal protection officers were reported to have carried out a dummy run at around 10pm on Sunday night, checking which entrances were being watched by photographers, which fuelled speculation that the Duchess's admission time was planned in advance. A spokesman for the Duke and Duchess said he did not know whether the couple had yet decided on a name for their son. When the Duke of Cambridge was born at the Lindo wing in 1982, his name was not made public for a week. His brother Prince Harry's name was disclosed when he and his parents left the hospital. The Archbishop of Canterbury, the Most Rev Justin Welby, was one of the first to speak of his joy on Twitter. Delighted for the Duke and Duchess of Cambridge as they welcome their baby boy. May God bless them all with love, health and happiness," he said. The Labour leader Ed Miliband added: "Many congratulations to the Duke and Duchess of Cambridge. I wish them and their son all happiness and good health. Deputy Prime Minister Nick Clegg said the "good news" would make the "whole country smile" as he offered his congratulations on Twitter. Boris Johnson, the Mayor of London, said: "Congratulations to the Duke and Duchess of Cambridge on their new arrival." Meanwhile Oliver Hicks, 31, a close friend of Prince William who has just completed the first recorded kayak crossing of the North Sea between Britain and Norway, said he was thrilled to hear the "fantastic" announcement. . Even Emma Bunton, the former Spice Girl, expressed her excitement, echoing the sentiment felt outside Buckingham Palace. It's a boy!!! Special times ahead for Kate and William," she said.