I was recently traveling to the UK to visit friends. I was detained at Heathrow and held and sent back to the US. The reason they gave is that I had past paystubs with me and a card that said good luck in your new journey. I had lots of clothes with me as I was staying for 3 months and had a return ticket. When can I reenter the UK? How long will I be flagged as someone who was denied entry? I am an American citizen. Yes they made my detention Hell.