The Duke and Duchess of Cambridge have introduced their baby boy to the world, standing proudly on the steps of the Lindo Wing with their son.
The royal infant, wrapped up against the cool Spring weather, nestled in the arms of his mother as the couple posed for pictures.
Kate looked in good health after giving birth this morning to her as yet un-named prince, who is fifth in line to the throne.
Hundreds of royal well-wishers gathered at the gates of Buckingham Palace this afternoon, as news of the new prince's arrival was announced in a tradition which stretches back to the 19th century.
The crowd waited patiently for the formal notice of the arrival of the fifth in line to the throne, which involves the presentation of a bulletin, placed on a golden easel in front of the palace.
The ritual dates back to at least 1837, when Buckingham Palace became the sovereign's official residence.
At 2:30pm senior footman Olivia Smith and footman Heather McDonald strode across the gravel at the front of Buckingham Palace to the roar of a delighted crowd, and placed the notice on the easel.
The bulletin had details of the birth, including the 11:01am delivery time as well as the signatures of the senior medical team who cared for the Duchess of Cambridge.
The notice read: 'Her Royal Highness the Dutchess of Cambridge was safely delivered of a son at 11:01 today. Her Royal Highness and her son are both doing well.'
Earlier Prince George and Princess Charlotte were introduced to their new baby brother for the first time.
The youngsters were taken to the Lindo Wing at St Mary's Hospital in Paddington, London, to meet the newborn Prince of Cambridge by their father the Duke of Cambridge.
The Duchess of Cambridge, who gave birth to the 8lb 7oz baby boy at 11.01am on patriotic St George's Day, was believed to be waiting in her private suite for her eldest children.
William, who was at Kate's side for the birth, left shortly after 4pm to collect four-year-old George and Charlotte, who turns three on May 2, from Kensington Palace.
George, who has spent the day at school and was dressed in his school uniform, appeared a little shy as he arrived, but Charlotte waved at the cameras twice, turning to do so and smiling as she walked up the steps.
Kensington Palace said the baby's name would be 'announced in due course', but Arthur is already the favourite with punters, according to the bookies.
The new prince is fifth in line to the throne, and the Queen and the Duke of Edinburgh's sixth great-grandchild.
The duchess was driven to the exclusive Lindo Wing before 6am on Monday in the early stages of labour, ready for the birth of their third child.
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