A man has been arrested on suspicion of child abduction, as a hunt was launched for a missing mother and two children.

The Metropolitan Police said Jamie-Leigh Kelly, 31, left a centre for vulnerable mothers and children in Colindale, north-west London, with her three-year-old daughter and newborn boy on Tuesday.

The force said the children are under care protection orders and were removed from the family assessment centre against the wishes of staff.

Ms Kelly, who has links to Thurrock in Essex and Havering, east London, then got into a blue Ford Fiesta with the children, which drove away at speed.

Police believe the driver of the vehicle was a woman and both driver and car have yet to be located.

On Wednesday a man in his 50s was arrested in connection with the investigation, on suspicion of child abduction and conspiracy to kidnap. He remains in custody in Essex.

Ms Kelly is described as white with green eyes, of slim build and about 5ft 4ins tall.

She was wearing a white jumper or long-sleeved t-shirt, white jogging trousers and white trainers.

Detective Superintendent Lewis Basford, who leads the Met’s Public Protection command in East Area, said the force was “extremely concerned” for the welfare of Ms Kelly and her children.

He said: “Jamie-Leigh, I am making a direct appeal to you to contact with us so we can ensure the children are safe and well.

“We know you have no intention for the children to come to harm, so we are asking you to please pick up the phone and have a conversation with us so we can meet with you.

“The baby may need medical care as he is newborn, so please put him first and contact us on 020 7175 0793.”

Mr Basford said they believe Ms Kelly is being assisted and urged anyone with information to call the incident room on 020 7175 0793 with information or call 999 immediately with live sightings.