A three-year-old girl was able to walk out of her nursery unattended and cross a road without anyone noticing.

Green Wrythe Nursery School, in Carshalton, has launched an urgent investigation after toddler Amelia Everest was able to wander the streets alone for ten minutes.

Amelia's mother, Amy Firmin, 19, said she will never send her daughter to the nursery again adding "she will find it hard to trust anyone now".

Amelia was able to walk out of the school grounds at about 11.45am and across a main bus route before being stopped by another mother ten minutes later.

Miss Firmin, from Peterborough Road, Carshalton, who gave birth to her second child two weeks ago, said: "Amelia had approached a van as her dad drives one and she thought it was him. Thank God she got back safe and sound. It could have been so much worse."

The young girl's Dad, Lyle Everest, 22, was walking towards the school when he noticed the woman with his daughter.

Miss Firmin said: "Lyle though the woman was trying to take Amelia, but when he found out what had happened he went into the nursery to see what had happened. They had no idea that she was even missing."

Isabel Ramsay, head teacher of Green Wrythe Primary and Nursery School, said: "We take the safety and well-being of our pupils extremely seriously, which is why I ordered an instant review to find out how this incident occurred.

"Work has already begun on a new double entrance to make sure that children cannot get out unaccompanied when the gate is open, and an extra member of staff has been brought in to oversee children being picked up by their parents and carers until the new gate is fully operational.

"Our ‘good’ Ofsted report from September 2011 rated the quality of care provided for all pupils as ‘second to none’, and I have spoken to all staff and reiterated, in the strongest possible terms, the strict procedures which we have in place to ensure that children can never leave the school unaccompanied."