I don't know what Rozzers you've been involved with, but they cant do that at all. If they did, you can report them and then they will get the b*llucking! This is not Nazi Germany or indeed Stalins Russia, and the coppers don't act quite like what you seem to think they do.
The police can search you if they suspect:
stolen goods, or
drugs, or
an offensive weapon, or
any article made or adapted for use in certain offenses, for example a burglary or theft, or
knives, or
items which could damage or destroy property, for example spray paint cans
They could even search you if you are behaving suspiciously.