Actually, it wasn't as rock'n'roll as it sounds. The story I heard was that some completely random person was drink-driving, and someone from the party saw this and took down their number plates. An altercation occured, and someone (else?) from the party called the police. When the police arrived, they reasonably assumed the drunk person had come from the party despite everyone's denials, and broke the party up. Huh!
You know, I don't think it's possible to call the police to break up a private party in the UK. You call the noise prevention hotline, only if it's a Friday or Saturday as that's the only times it happens, and if it's bad enough then they call the police. They Do Things Differently Here.