Some years ago I was flying into a very congested London Heathrow Airport when I heard the following exchange with Heathrow Approach.
Heathrow: “Speedbird 123, what is your position in the hold at Lambourne?”
Speedbird: “We are just turning outbound at flight level 200.”
Heathrow: “Roger, Speedbird, could you possibly cross Lambourne inbound at 3000 feet?”
Speedbird: “Roger, I could probably make that, but I doubt if I could take my aircraft with me.”
John Marshall