Ah - the dear old Litter Tray in Artillery Row, yards from Buckingham Palce indeed, approximately 1100 of them!! It isn't as if the pub was a nice little Westminster snookery...it is as rough as a badger's ringpiece in there.
Ah, you are showing your age now! That was the three quarter lancers and the "Rarely Irish" Rangers as I recall...over who had the "walking out" rights at the time. Strangely I can find no reference to this major running battle on t'interweb but I recall the local television going on about it for weeks.
My only comment about this is that it is an utterly disgraceful show....... where were the Micks?
Might have been late seventies Mistersoft! I believe that it was kicked off by the return of the lancers from NI who accused the Rangers of being a bunch of plastic paddies and war dodgers. Stung by this assault on their Birmingham/Liverpool/anywhere other than Irish honour, a rumble was arranged. A very large number of soldiers from each regiment then got it on...cue major press and civic pontification and lots of Colchester vacations!