AIMS: Explore children's gambling behaviours, specifically amongst those aged 11-15 who are not legally entitled to buy National Lottery tickets. Analyse gambling behaviour trends over time. METHOD: Randomly selected secondary schools were approached to participate in the study, with classes selected at random. Whole classes would fill in a survey. 2,739 pupils in 113 schools participated (school response rate 20%). FINDINGS: 23% of young people took part in some form of gambling in the past week, 8% placing a private bets with friends, 9% have played a fruit machine, 6% played Lotto and 7% scratchcards. Those who play National Lottery games are also more likely to gamble on other types of game. Children who play online trial gambling games show a greater propensity to engage in 'real' gambling for money. DISCUSSION: The appeal of various forms of gambling to the same children reinforces the importance of collective regulatory action to tackle underage gambling, as well as action against individual forms of gambling. Monitoring children's access to free games, and ensuring they do not encourage gambling for money among under 16s, will continue to be important.