This question already has an answer here:
I am an Indonesian national and planning to visit UK on July 21. But for some reason the embassy give me a UK visa with the validity date start from July 22. I already bought a ticket with the arrival time at Heathrow on July 21 at 09.30. Since it's a promo tickets, I can't change the date and refund it.
My question is, is it possible for me to pass through the border control with my visa, which won't be valid yet at the time? Or if it's not possible, can I wait at the airport and go pass the border control after midnight on July 22? Is there any transit hotel or other facility that I can get some rest while waiting?
Thank you very much.