Originally Posted by
HarryKUK
Specifically because it's on two tickets? Or would he need that anyway even on one ticket?
I don't see why there would be two separate rules, surely UKBA won't care if he is or isn't on one ticket?
UKBA probably don't even know what that means, but (unless you really need to go landside) they aren't the problem here.
Your problem is boarding the BRU-LHR sector.
In my experience, BA is totally relaxed about me transferring through countries on separate tickets without a visa I would require. But their contractors at BRU might take a different view.