Samantha Cameron remains in hospital for another night

Mrs Cameron has been at the Royal Cornwall Hospital in Truro since giving birth to daughter Florence Rose Endellion.

A Downing Street spokeswoman said said: "Both mother and baby are doing very well."

Folding beds are available for fathers to sleep overnight in the maternity unit's private side rooms, which are given to women who have Caesarean sections.

The hospital said the length of mothers' stays after a Caesarean was based on their individual needs, but they were usually kept in for about 48 hours.

The couple have received congratulatory messages from the Queen, the Prince of Wales, Gordon and Sarah Brown and French President Nicolas Sarkozy.

Their elder children, six-year-old Nancy and four-year-old Arthur Elwen, have visited their sister, who weighed 6lb 1oz.