Jester - you must resist the attractive temptation of 'taking the law into your own hands'. Don't shout at them, don't chase them, don't touch them, don't restrain them unless you want to invite the '4 o'clock knock' from Plod. A pound to a pinch of dog turd if you do any of the above their feckless parents will report you and you will be prosecuted ... you're an easy target for the forces of law and order. We've all read in the press the outrageous tales of decent folks being criminalised because they felt helpless before the tide of teenage anti-social behaviour. You posted that "St.Benet Biscops say it's out of school hours...not their problem" ... well of course it's their problem; if these little shits can be identified as being pupils there then they are bringing the School's name into disrepute and can/should be disciplined. If the Head doesn't do anything then go over his head to the Chair of Governors and send a copy of the complaint to the Top Bish at the Diocese. Try to get the local press involved ... they loves these type of stories ... and there's nothing more potent than press involvement to oil Plods works (and the School's). Shame them into action! Others here have talked about Asbos (conditions can include 'exclusion zones'), maybe worth instigating but I don't know how. Anyway, I blame it all on Esther Rantzen for founding Childline, that august body dedicated to child protection. Trouble is they also protect the shits from their parents who try to discipline them; how many parents out there have heard the refrain "if you ground me/smack me/hold-back the pocket money/no telly/send me to my room/ I'll call Childline and complain of abuse"? Of course some decent parents run scared whilst the feckless lot couldn't give a monkeys what their brats are up to. Oh dear, I'm morphing from a Guardian reader into something that takes The Daily Mail!