In 1954 I was a National Service Elec Mech Air stationed at RAF Waterbeach with 56 Sq RAF.
There was one hell of an exercise where we worked dawn to dusk for I think two weeks,slept in the barracks but everything else was done in tents out at the edge of the runway.
On one day two Belgian Thunderjets appeared and dropped flour bags on us. Great we thought, we're out of this war. No such luck, carry on lads
That must have been Battle Royal ,but nobody told us, we were just gash NSA bloody nuisances.
There are a couple of articles on Battle Royal in the Flight Magazine Archives web site