Natasha Adekusibe, 22, has not been seen since she left her home in Charlton, south east London, early on Thursday morning.

Neighbours found her two-year-old son wandering on the street near their flat dressed only in a nappy and shoes at about 3.45pm on Friday.

Police believe the boy was left in the house but managed to climb on to a chair to open the front door and crawl underneath a metal security grill.

A Metropolitan Police spokesman said Ms Adekusibe bought cigarettes from a Costcutters in Charlton on Wednesday night and was seen by staff walking in the direction of her home with a man, described as black and wearing dark clothing.

CCTV images showed she returned home alone at about 10.50pm that night, but left at 5.15am the following morning carrying a rucksack and wearing a black and white print short sleeve top and jeans.

She caught a train from Charlton station and police believe she got off at Greenwich station, south London, at about 5.40am.

Police have released two CCTV images of her in an effort to trace her.

She is described as a light-skinned black woman, 5ft 5in tall and of medium build with shoulder-length dark hair, which is sometimes worn in a ponytail.

Chief Inspector Brian Cherek, from Greenwich police, said: "Natasha has not gone missing before and is described as a loving mother so this is very out of character. We are obviously concerned for her welfare due to the surrounding circumstances of her disappearance. We know that Natasha has been under a lot of pressure recently, and if she has simply gone away to seek some time alone, I would urge her to make contact so that we know she is okay and to reassure her that her son is being cared for."