Police and social services are trying to trace the parents of a nine-year-old boy who attempted to push a trainee social worker on to the tracks at Plaistow Underground station, east London.

The child from Haringey was arrested, but because he was under the age of criminal responsibility, police could not charge him and had to hand him over to Haringey's social services department. British Transport Police arrested the child, who for legal reasons cannot be identified, after he twice tried to force the 39- year-old woman from Forest Gate off the platform on 13 July.

Detective Inspector Alan Wilson, of British Transport Police, said: 'It's outrageous that we had to totally rely on Haringey social services.'

The parents, who live together, are understood to be former travellers. They have six other children.