Heathrow publish several satellite phone numbers for use by airliner crews.
Not sure why these are sat phone numbers because a sat phone cal dial land numbers just the same (albeit much more expensively).
However, airliners would tend to have fixed sat phone installations rather than handhelds (that's my guess). I have tested handheld sat phones in the cockpit and they work OK so long as you assure line of sight to the satellite.