On in particular was a Jet Prop out of somewhere like LFAT that was levelled at FL090 (on the way to something like FL250 - for a trip to the North of England) for the handoff from France to the UK. They were handed to London Info and then had to stooge around London at low level.
But surely level at FL090 would but him right in London's airspace just a few minutes after take-off? I find it hard to believe that it wasn't some sort of mistake...I mean a reasonable amount of IFR traffic presumably comes from Northern France into the UK even at piston/turbo pro levels.