The
April 2014 issue of "Air Pilot" provides this:
"...Operation Granby, when Cathay leased a 747 Freighter to the MoD based initially out of Stansted, and subsequently Brize Norton. Operations were conducted under an RAF callsign of Ascot 888 (a very lucky number in Chinese) flying 'non contentious' supplies to Dhahran. The aircraft (VR-HVY) was painted completely white and,as a result, became known to the crews as the 'Stealth Freighter”.