Originally Posted by
stifle
I think if you get to the UK you will be fine. At worst if the UKBF chief immigration officer thinks you're a wrong'un and going to abscond, they will detain you overnight and put you on your booked plane in the morning.
The bigger risk is being refused boarding at the start of your journey by a check in agent with their own view of the rules.
Surely the worst cases (other then being denied boarding right at the start) is the OP being sent back to their departure point which the UKBF may be more likely to do than detain and send on their merry way the next morning.