A 10-month-old baby boy and his two-year-old sister were dumped in a dark and freezing city centre street.
The children were found shivering in a buggy in Plymouth wearing only lightweight clothes, after passers-by, alerted by their distressed cries, called the police.
A set of house-keys, a purse and a handbag were found in the buggy, which led officers to the children's mother. The woman claimed to have been the victim of domestic abuse.
The children were last night in the care of their grandparents, after police removed them from the scene in Western Approach in the centre of Plymouth, Devon.
The mother has taken out an injunction against her former partner, although both parents are said to have voluntarily agreed to meet officers.
A police spokesman told reporters said: 'The children are safe and well. Officers from the child abuse investigation team are inquiring into how they came to be in the street alone.'