The Duchess of Cambridge and Prince William were given the congratulations of a nation last night on the birth of their baby son.
News of the royal arrival broke at around 8.30pm, when a statement was issued by Kensington Palace.
Prime Minister David Cameron said it was "wonderful news" adding: "I am sure that right across the country, and indeed right across the Commonwealth, people will be celebrating and wishing the royal couple well."
And the news was warmly welcomed in the Westcountry which played host to Prince Edward yesterday as the news broke that the Duchess of Cornwall had gone into labour.
"It is a very happy days for both parents and the wider family," St Ives Liberal Democrat MP Andrew George said last night.
"I'm sure the whole nation will be celebrating."
I am very pleased for them," added Councillor John Pollard, leader of Cornwall Council. "I hope all is well."
Chairman of Somerset County Council, Councillor David Fothergill, said: "I would like to offer the congratulations and best wishes of all the people of Somerset to the Duke and Duchess of Cambridge on the birth of their son. I hope he brings them a lot of joy."
Oliver Colvile, Conservative MP for Sutton and Devonport said it was "brilliant good news".
He added: "I'm delighted for them and we now look forward to hearing what the name is going to be."
George Eustice, MP for Camborne and Redruth, said: "This is wonderful news and I am sure everyone in the Westcountry will want to congratulate Kate and William on the new addition to their family."
Alison Seabeck, MP for Plymouth Moorview, said: "It's lovely news. Everybody will be absolutely delighted as they are at the birth of any new baby, royal or otherwise. I'm delighted for Kate."
And Alexandra Christie, of Plympton, was among mothers to also give birth yesterday – her baby boy being named Zachary – and said: "It's just made an exciting day more exciting."
Meanwhile, Exeter Cathedral has created a special baby book for the people of Devon to sign to congratulate the Duke and Duchess of Cambridge on the safe arrival of their baby son.
Kensington Palace had earlier announced the baby had been born at 4.24pm and weighed. 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," it said.
"Her Royal Highness and her child are both doing well and will remain in hospital overnight."
The baby weighed 8lbs 6oz and was born at 4.24pm. The Duke of Cambridge was present for the birth.
A Buckingham Palace spokesman said: "The Queen and Duke of Edinburgh are delighted at the news."
Soon after the palace announcement was made, a notice giving details about the baby – the third-in-line to the throne – left St Mary's Hospital in London by car for Buckingham Palace.
It had been signed by the Queen's gynaecologist Marcus Setchell, who led the medical team that delivered Kate's baby.
The notice was placed on an easel in the palace's forecourt just like the announcement of William's birth on June 21, 1982, a traditional element of theatre in marked contrast to the modern age of e-mails and Twitter.
The new royal baby will be the Queen's third great-grandchild and is destined to be crowned monarch.
He will be the 43rd sovereign since William the Conqueror if, as expected, it follows reigns by the Prince of Wales then William. Kensington Palace said "The names of the baby will be announced in due course."
The Prince of Wales issued a brief 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."