Updated

LONDON (AP) — British Prime Minister David Cameron's wife gave birth to a baby girl Tuesday, while the couple were away from London on their summer vacation.

Cameron's office said the baby was born at the Royal Cornwall Hospital in Truro, a town in southwestern England. The couple had been spending a break in Cornwall with their son and daughter.

Samantha Cameron, 39, had been expected to give birth in September, and arrangements were in place for Cameron to take paternity leave next month, but the prime minister said he and his wife dashed to hospital this morning.

"It was a bit of a shock but I always thought it was possible," Cameron, 43, told reporters outside the hospital. "It all happened very, very quickly."

Cameron said the baby had been born about midday and was "absolutely thrilling, really exciting" news.

His office said the baby weighed 6 lbs 1 oz (2.7 kilograms) and confirmed the child and Mrs. Cameron were doing well.

"The prime minister and Mrs. Cameron would like to thank the doctors and nurses at the hospital for their help and kindness," Cameron's Downing Street office said in a statement.

The family have two other children, Elwen and Nancy. Their severely disabled son Ivan died last year aged 6.

Cameron has often used scenes of his domestic life in his political campaigning, including videos in which his children are heard — but not seen — interrupting their father as he addresses the camera.

A spokesman for Cameron's office, who spoke on condition of anonymity in line with policy, said the prime minister planned to take some paternity leave, but would not say how long he will be away from his duties. He said it was not yet known if Cameron will return to work when Britain's Parliament reconvenes on Sept. 6 following a summer recess.

Bookmaker William Hill said it had opened a book on the likely name of the Cameron's baby girl — with Marnie, Agnes and Enid the favorites. Odds on the Camerons naming their daughter Margaret — after the iconic leader of Cameron's Conservative Party Margaret Thatcher — were at 50-1, spokesman Joe Crilly said.

Cameron told reporters he would likely have little say in the decision, and said his wife was already studying a book of Cornish names

"It was very exciting having a baby in Cornwall, so we'll have to have something Cornish in the middle," he said.

One of Cameron's recent predecessors, Tony Blair, also had a newborn while in office. Blair's wife Cherie gave birth to son Leo in 2000.