This question already has an answer here:
I am a Indian National, currently studying in San Francisco on a Valid F1 visa. I came to India for a month long visit and will be leaving via Heathrow. Unfortunately i have a 18hour layover there. Will I be able to get out of the Airport without a Visa? My flight lands 6 pm in the evening and leaved 1 pm the next day. I basically plan on just hanging out for the night and staying a hotel later on.
I really dont think the immigration people expect you to stay at the airport for the whole 18 hours. I was reading the info in the other topics as well as the UK visa website. But nowhere did I find a clear answer, mostly everyone has just quoted what has been stated on the UK website. Is there anyone who has been under the same situation?