The baby was found by a bin collector outside All Saints Church shortly before 12.45pm yesterday (March 25).
The baby, who was declared dead at the scene, has been confirmed by police to have been a newborn boy.
Superintendent Owen Renowden of the Metropolitan Police gave an update (March 26) outside the church near where the baby was found just off Talbot Road.
He said: “As shocking and tragic as this is, my priority remains with the mother’s welfare and health.
“We are really worried about her wellbeing as she will recently have given birth.
“I know she will likely be feeling very frightened and going through an extremely difficult time.
“If you are the baby’s mother and see this today I want to appeal directly to you to come forward and seek help.
“My priority is to help you – to make sure you receive medical assistance.
“You can do this at any time by attending any hospital, police station, or by calling the emergency services.”
He said local officers had been working “through the night” following the discovery.
He added: “I want to praise the professionalism in particular of the local refuse worker and also the responding emergency services who I know will have been deeply affected by the incident yesterday.
“I know the community here have been concerned by what has happened and we will be continuing our close work with our partners to support local people.”
Officers are due to remain in the area of the church over the coming days and can be found at a community drop-in at Fort Close today (March 26).
The officer also appealed to anyone with information who was in the area or had seen somebody with the bag to come forward.
People can do this by calling 101 or online using reference 1879 of March 26.
