Three firefighters from Old Kent Road fire station helped to deliver a baby boy on Monday morning.
"I opened the car door and found the woman laying down and I could just see the tip of the baby's head so I realised there wasn't a moment to lose," said watch manager Stewart Gordon.
"Meanwhile firefighters Bob Bennett and Mustafa Osman administered oxygen and kept her calm.
"Just as the head was starting to show London Ambulance Service crews took over and cut the cord.
"Our driver Firefighter Peter Guppey suggested that the boy be called Oscar after the tactical mode we were in but I suppose it could be Stewart, Bob or Mustafa.
We've not heard from the mother but everyone at the station hopes that her and the baby are doing well. It's the first baby we've ever delivered but shows how varied our job can be."
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