Pimms history and recipe

Came across this review of Pims No. 1, which contains an interesting history to the drink. Also a recipe to make Pimms in your kitchen:

Take two measures of quality Gin (preferably with greater than 40% abv) i.e. Tanqueray or Bombay Blue Sapphire, two measures of red vermouth, and one measure of orange curacao and you have the alcoholic part of Pimms No.1 cup. It is the Gin that makes it No.1 cup, the only other cup sold in Britain is a vodka-based cup, Pimms No.6. Cups No. 2 to No. 5 are no longer sold in Britain, and it is not surprising given the fact that they are made of Whisk(e)y, Brandy, Rum or Rye. The bottle is a very simple design - clear white glass and with a classical red on white label - the bottle resembling a typical round whisky bottle. As a drink the pre-mixed stuff is perfectly quaffable, however, once you have discovered the self-made stuff I doubt you will ever revert to the bottled stuff.

I thought there might be a bit more to it than that, so let's say this is an experiment for this summer.