P256 ORACLE 256 Tue 1 Oct CEN 2147:47    Review by Steve Rjgan GOT A CRAZY idea for a cop series? Send it to BBC1 bosses - they'll buy any old rubbish. The more preposterous the idea, the more likely it is to succeed. After last week's home-made disaster with Specials comes Cop Rock by Steve Bochco, creator of Hill Street Blues and LA Law, who ought to know better. It's a mix of inner city violence, trigger-happy cops - oh yes, and song and dance routines! In the ghetto, drugs dealers rap. At city hall, the mayor belts out a ballad. I ask you?! TV Plus Guide 250 Local Adverts 270 ORACLE VIEWERS HOLIDAY OFFERS 378/9 Highlight ITV Films Adverts TV Guide