Tickets    Students and childrenhttp://www.tfl.gov.uk/tickets/14554.aspxIf your child is:    Travelling with an adult (up to four children per adult)    Or using a 5-10 Zip Oyster photocardThey can get    Free travel on Tube, DLR, London Overground and some National Rail servicesYour child can also    Travel free on London's buses and trams unaccompanied and without an Oyster photocard