Originally Posted by
UKtravelbear
departing airside would require you to get to the arrivals level (likely involving some sort of escort) so you can formally re enter the UK.
Is this still the case? When I was forced to leave Departures after my flight was cancelled back in 2012, there was an 'escape route' straight back to baggage reclaim that we were all ushered through.
Probably would still require an escort though. I'm sure that they must have a process in place for last minute situations if you ask at the relevant customer services desk (e.g. I'm sure "there's been a family emergency and I need to cancel this trip" can't be that uncommon).