UK PM back at work after birth of son

British Prime Minister Boris Johnson is back at work at his Downing Street office after being present while his fiancee Carrie Symonds gave birth to their son, his political spokesman says.

"The birth took place at an NHS (National Health Service) hospital in London and the PM was present throughout," the spokesman said, declining to give any more details of the birth.

"The PM was with Ms Symonds this morning for the birth of their son and is now back at work in Number 10 ... I think later in the year he'll take a short period of paternity leave."