paull,
1-Vertical separation is the only thing that is enforced between LCY and LHR tracks.
2-There was none in this case.
That leaves me wondering why all the ATC chaps on here did not say
"Yes, we know about that it was a level bust" , instead we seem to have pages of discussion telling us that it did not happen. Scary.
Can you point out where I or anyone else said the incident in question did not happen?
I was responding to (incorrect) assumptions about the way the airspace in the area is managed in order to try and clarify things for at least one contributor to the thread.
I have no first hand knowledge of the incident in question as I wasn't working when it apparently happened so have refrained from commenting on any specifics and if I did have inside knowledge of a specific incident it's unlikely I'd share it here to any great extent anyway.