Salisbury, ignore rugleyboy - he is a dinosaur, an employer from the past when the guys in charge could treat the employees exactly as they liked, and get away with it. No employer can treat you like that these days. Take mandimoo's advice - put in a complaint - let it be known that you are not prepared to be humiliated and demeaned like that, even if you did make a mistake. Everyone, no matter how lowly their job, is entitled to dignity and respect. If you get any cr@p because of your complaint, put in another one - if they sack you because of it, go to a tribunal. Employers like the one you have need to be dragged kicking and screaming into the twenty first century, and forced to treat their employees with respect.
Go for it! Stand up for your right to dignity.
Best of luck.