OK, if that is so, could you please explain the rules/law for us?
As far as I know it is prohibited on all carriers based in Europe (naturally, this is as far as the CAA/JAA can go!). There is no requirement for foreign airlines to comply with the rules so it'll be company rules/captains descretion. I got a ride into Heathrow last year on the flight deck with an airline from the Sub-continent.