I had a stone caught between the caliper and brake disc recently, made the most horrendous noise... scared the sh*t out of me....!
Haha this happened to me a few weeks ago, drove to work, dont think I used the brakes for 10miles or so on this B road, then got to a set of lights in a small town, and this almighty screeching sound came from the brakes, and wouldnt stop, also scared the crap out of me as to start with I couldnt tell where the hell it was coming from. thankfully it stopped by the time I go to work. Slightly embarrasing creaping along at the busy lights with loads of mums walking their kids to school lol and this super high pitch screeching noise coming from my car lol.