Samantha Cameron is pregnant with fourth child

Samantha Cameron, wife of the Conservative leader, is expecting her fourth child, it has been announced. She and David are said by a Tory party spokesman to be "completely thrilled" by the news.

The Camerons lost their oldest son Ivan, who had cerebral palsy and epilepsy, in February 2009. They have a son and daughter, six-year-old Nancy and four-year-old Elwen.

Samantha, who is 38, is due in September, raising the possibility of another child being born to a sitting PM, should the Conservatives win the general election. It would be only the second in 150 years. Tony and Cherie Blair had their fourth child, Leo, while residing at Number 10.

In good political style, the pregnancy was heralded by a manifesto. Last September, David Cameron said: "I don't believe Britain is over-populated. I don't have any plans to reduce it. I would quite like to add to it, personally, by quite possibly one, at some stage in the future."

Earlier this year, David Cameron revealed his wife would take a more active role in the election campaign than previous political spouses have, calling her his "secret weapon". Some might say she has deployed her trump card. ·