I was strip searched at Luton one day when the metal clip on my trousers set of a little beep on the hand held metal detector. Yet I can go through screening in the US set of the walk through metal detector and all they want to see is your ankles. Haven't been through Stanstead, but Heathrow are similar, it is just a horrible experience to go through before you start your days work. One day you can go through without any hassles and the next its the spanish inquisition.