How do I get street preachers to leave me alone?

[Emrinne]

Here in England a lot of American groups of Christians seem to think it's fine to set up a loudspeaker in the street and try and mass convert us to their version of Christianity.
It makes me very uncomfortable when they approach me to try and convert me, they rarely listen when I say "I'm not interested" so I tend to say "I don't need converting" - it allows them to make whatever assumptions they like. If they bother me further I say "I'm busy, have a nice day". Perhaps that could work for you?