Samantha Cameron has given birth slightly ahead of schedule. The baby girl, who has not yet been named, was originally due in September.
This is their fourth child, and Downing Street have said that both mother and baby are doing well.
A Downing Street statement said:
The Prime Minister and Mrs Cameron are delighted to announce the birth of their fourth child, a baby girl. Both the baby -- who was born weighing 6lbs 1oz -- and Mrs Cameron are doing very well. The PM and Mrs Cameron would like to thank the doctors and nurses at the hospital for their help and kindness.