The Duchess of Cambridge has given birth to a boy, the third in the line to the throne who may one day be the King.
"Her Royal Highness The Duchess of Cambridge was safely delivered of a son at 4.24 p.m. [London time]," royal officials said in a statement.
"The baby weighs 8lbs 6oz. The Duke of Cambridge was present for the birth. The Queen, The Duke of Edinburgh, The Prince of Wales, The Duchess of Cornwall, Prince Harry and members of both families have been informed and are delighted with the news. Her Royal Highness and her child are both doing well and will remain in hospital overnight."
Cheers and singing went up in front of the Lindo Wing as news filtered through of the birth. Some people started dancing while others locked arms and sang.
"We could not be happier," William, the Duke of Cambridge, said in a short statement after the birth.
Prince Charles, the Duke's father, also expressed his joy 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."
Canada's Governor-General, David Johnston, extended his congratulations to the new parents.
"Sharon and I have five wonderful daughters and ten delightful grandchildren and know well the elation that a new arrival brings to a young family," Mr. Johnston said in a statement. "We know that this happy event brings great joy not only to Their Royal Highnesses, but to the entire nation as well."
The new baby will be receiving a gift of Canadian-themed children's books from Mr. Johnston and his wife, who are also inviting people to sign a Web-based book of congratulations for the family.
Canadian Prime Minister Stephen Harper extended "best wishes of health and happiness" to the Duke and Duchess of Cambridge from him and his wife, Laureen.
"The arrival of the newest member of the Royal Family, a future Sovereign of Canada, is a highly anticipated moment for Canadians given the special and warm relationship that we share with our Royal Family," Mr. Harper said in a statement from the PMO.
"This new beginning reminds us of the remarkable and enduring relationship our country has enjoyed with generations of the Royal Family. We recall with fondness the years of unfailing service by Her Majesty Queen Elizabeth II and His Royal Highness The Duke of Edinburgh and their deep affection for and loyalty to this country. We also recall the Royal Tour by The Duke and Duchess of Cambridge who were so warmly received in Canada only two years ago. We look forward to their return to Canada and to being able to introduce their child to Canada and all Canadians."
Cian Horrobin, a spokesman for the Monarchist League of Canada, said the birth marked the the beginning of a lifelong relationship for Canadians with "this boy who will one day be our king."
Even those opposed to the monarchy welcomed the prince's arrival.
Tom Freda, director of the organization Citizens for a Canadian Republic, said any news involving the Royal Family renews the debate over the relevance of a monarchist system, "and debate is good."
The announcement of the baby's birth came after a long day that began with the Duchess going into labour sometime before 6 a.m. London time. She was taken to the private Lindo Wing of St. Mary's hospital in a car from Kensington Palace with her husband, the Duke of Cambridge. They entered through a back door, avoiding the media throng that had been camped out front of the hospital for weeks.
As the day wore on, hundreds of people lined the street out front of the hospital, eager to catch a glimpse of something. "When I heard it on the radio I shouted to my sister 'the baby is coming,' " said Jacqueline le Patourel, who rushed over to the hospital while on her way to Paddington station to catch a train to her home in Cornwall. "I had to come and take a picture for my sister and my American friends."
Teba Diatta got so excited she baked a sponge cake and brought it with her from her home in York. The icing on the cake read: "Come on Kate we can't wait give us something to celebrate."
"I just think [the Duchess and Duke] represent my generation very well," said Ms. Diatta, who also painted her cheeks with Union Jacks. She had been hoping for a girl named Georgia.
Most of the betting had been on a girl, with the most popular name being Alexandra. Bookies had taken far fewer bets on boys with James and George as the names most favoured by bettors.
A girl would have also made history since Britain has changed the law of succession to allow for succession of the eldest child, regardless of whether it is male or female. The law still has to be approved by the 16 countries, including Canada, that have the monarch as their head of state. That has yet to happen and in Canada two law professors in Quebec have challenged the way the federal government has approved the change to succession. The professors argue the change requires involvement of the provinces and they say the issue gets at the heart of the monarchy's role in Canada.
If the lawsuit succeeds there is a possibility that Britain and the other realms could approve the change and the baby would one day become Queen. But if the Duke and Duchess had a boy, he could become the King of Canada.
So far the only other countries to adopt laws to recognize the change are St. Kitts and Nevis, and St. Vincent and the Grenadines. However all of the realms agreed to change their laws during a Commonwealth meeting in 2011. The law also does not have to be in place when the child is born and can take effect later.
Not everyone who stopped by the hospital was a supporter of the royals. Painter Kaya Mar arrived with a satirical portrait of the Duchess clutching a baby wearing a crown with a corgi at her feet. "I'm a republican," said Mr. Mar who came to Britain from Turkey 40 years ago. The monarchy "is a corrupt institution…The English love to live in the past as a comfort."
Danny Shine also arrived with a megaphone and began berating the onlookers and the journalists for making the event such a spectacle. He was shouted down at times, but pressed on. "I'm trying to get people to think outside the box," he said afterward. "I want them to question why this person being born is any more special than the rest of us." Mr. Shine, a professional singer, said he wanted to talk some more, but he had to leave to pick up his children.
By far the majority of people were like Alex Bonacarti, a tourist from New York who came out of curiosity. "We heard about it and decided to come over since our hotel isn't far away," she said referring to her friend Cheryl Moran who is from Buffalo, N.Y. The two are in Britain for a couple of Bruce Springsteen concerts. When asked if she would consider skipping the concerts to wait for the arrival of the royal baby, Ms. Bonacarti snapped: "No way." She has seen Mr. Springsteen 90 times and not even a future monarch will keep her away.
Melvyn Wood of Terre Haute, Ind., ended up in St. Mary's Hospital after falling down in a subway station. As he left in a wheelchair Monday with his wife Barbara, he stopped to marvel at the mass of people. Ms. Wood said she had been following the royal pregnancy in the U.S. for weeks and she was excited to be at the same hospital. "I followed their wedding," she said referring to the Duke and Duchess's marriage in 2011. "I would stay up all night to watch it."
She added that she wished the U.S. had a monarchy. "I think it would be exciting. It would be nice to have a King and Queen." Mr. Wood agreed and added: "I guess [Americans] like kings and queens."
With a report from Steven Chase and Associated Press