Originally Posted by Sjoerd
I have come through UK immigration Control with a non-UK passport about 50 times and it has always been a non-event. No questions asked and a smile most of the time.
Prior to my one poor experience with US immigration (and my detention by Polish authorities earlier this week which vaults them into number two on my disliked immigration agencies list), the worst experience I ever had was at Heathrow. I must have been about 19 years old and non-revving back to college in Atlanta from India when the immigration officer decided to be a prick and ask me how many times I had visited the UK before. When I told him "many", he insisted on a number. Evidently "2-3 times a year since I was born" was not a good enough elaboration either. He then made me stand off to the side facing the wall like a punished schoolboy and count passport stamps. I finally came up with a figure around 55 and he stamped me through without any more hassle.
Apart from that single incident, the biggest hassle I have had with Heathrow immigration is when I try to talk them into stamping my passport. No luck on that front during the last year or so alas.