A newborn baby girl has been found wrapped in a towel in a shopping bag in east London, police said.
The baby was discovered in Newham in sub-zero temperatures by a member of the public who kept her warm until paramedics arrived.
Met Police said she was unharmed in any way and is safe and well in hospital.
Police said they were “extremely concerned” for the welfare of the girl’s mother and appealed for her to get in touch.
Officers were called at about 21:15 GMT on Thursday when a dog walker found the baby at the junction of Greenway and High Street South.
Ch Supt Simon Crick said the walker’s action in keeping the little girl warm “contributed to saving the baby’s life”.
He said: “Our thoughts now turn to the baby mother; we are extremely concerned for her welfare as she will have been through a traumatic ordeal and will be in need of immediate medical attention following the birth.
“Trained medics and specialist officers are ready to support her and we urge her to get in touch by phone or walk in to the nearest hospital or police station.”
He added: “Please know that your daughter is well, and no matter your circumstances, please do seek help by dialling 999.”
The force is also asking for anyone who thinks they know the mother to contact them.
The infant is the third to be found in Newham since 2019, with a girl left in a park in February 2019, and a boy on the street in January 2020.