The news was greeted with shrieks of joy and excited applause by hundreds of Britons and tourists gathered outside the hospital and Buckingham Palace.
Revellers staged impromptu parties at both locations, and large crowds crushed against the palace gates to try to catch a glimpse and a photograph of the golden easel placed there to formally announce the birth.
In London, gun salutes were fired, celebratory lights came on, and bells chimed at Westminster Abbey, where Prince William and Princess Kate wed in a lavish ceremony that drew millions of television viewers worldwide.
