They are the kind of jokes you can do without - you pick up the phone to hear you are ordered to fight in Bosnia, debt collectors are on the way round to reclaim your television set or to say you owe money to support mystery illegitimate children. Using voice-activated computers, these are the latest 'phone services' to have been dreamt up in Britain, and after an avalanche of complaints the telephone watchdog which monitors such services has decided to act. The 'jokes' are played by colleagues at work giving you a number to call or passing on a call they have made to your extension. Voice-activated computers give the illusion that you are actually having a conversation with an extremely dogmatic person who will not listen to what you are saying. Every time the victim speaks they reply with something along the lines of 'Don't interrupt me' and then continue their attack. Office workers use them to embarrass colleagues or employers - all at considerable cost - the premium rate calls cost up to 49p (HK$6) a minute. Among the joke calls on offer is a bogus order to go and fight in Bosnia, telling victims they must turn up at a large Army base the following morning for bayonet practice. Another one involves a debt collector coming around because of unpaid tax. He hints that he will go away if bribed. The Independent Committee for the Supervision of Standards of Telephone Services has now begun to impose heavy fines on the joke lines and is considering a new rule that messages must say from the start that they are only for entertainment.