A Polish woman has become only the second person to give birth on London’s underground rail network since it opened 146 years ago, the transport authority confirmed on Friday.

Julia Kowalska was travelling with her sister on the network’s Jubilee line on December 19 when her contractions started.

She got off at a station in Northwest London, and gave birth to a healthy baby girl in the supervisor’s office, assisted by an ambulance crew.

The only other birth recorded on the 275-station underground network happened in 1924 when Marie Cordery was born at Elephant & Castle, operator Transport for London said.