Heathrow was touted to have such facilities installed / implemented but obviously this sort of operation takes up a lot of space. From what I heard (and by no means fact) BAA were unwilling to give up the space for what would be a non-commercial activity. In other words any space they do have is to be taken up by shops, shops and more shops. US immigration means fewer shops and less money by their thinking. Would be good though. I'd much prefer to be treated like a piece of sh*t before the flight and get it over with than have it all to look forward to.