My wife and I flew into Glasgow last July from Vancouver, Canada. There was a considerable line at the passport control, but it still took only about 20-25 minutes to get through. It might have been quicker had I not made the mistake of answering the question about purpose of the visit by revealing that I was in Scotland to play with a pipe band. This admission seemed to arouse suspicions that I might be getting paid for my services (I wish!) and led to a rather rigorous questioning on the subject. Customs was no problem; we just walked through.