For Wednesday's grudge match, Northern Rockers are asked to dress in BLUE tops; that's because it's fookin freezing Oop Narth. The Beautiful South are asked to dress in RED tops, reflecting the warm glow Dahn Sarf.
If you do not have the right colour, then a cloth cap or a bowler hat will suffice.
This might have been amusing if it wasn't for the fact that Harpenden, the quintessential Southern town, is actually in the North.
Suggestions for next year: people who live in million pound houses against those who do not; people who own BMWs/Mercedes against those who do not; baldies against hairies; beardies against the shaven; the profane against the polite (that won't work for obvious reasons); Brexiteers against Remoaners (it'll probably still not be resolved by then).