A friend of mine is travelling to the UK soon from the Middle East without a return flight booked. She works for a Middle Eastern airline and is only able to book significantly reduced plane tickets with her airline a day or two before the flight.
What I would like to know is what she can expect UK side, once she lands, from immigration control? Looking around on the internet, it appears that people are allowed into the country without a return flight but I couldn't find any more detail than that. i.e. Will she be allowed straight through immigration or will she have to go through a lengthy landing interview?
She is a Thai national, she currently holds a 6-month tourist visa and will be staying with me for the duration of her trip. If relevant, she spent 3 years living in the UK as a student (she left 2 years ago) and only intends on staying for 4 days.