Never having attempted a standard Battenberg before I was thrilled with how this potentially unstable variant came (and held) together. With an event celebrating a UK based organisation coming up I wanted to do something relevant, and this just popped into my mind. It still seems likely to me that someone will have already done it before.
I have to admit to having used store bought the icing and the marzipan. Marzipan I can do but needed a lot at short notice, which also influenced the decision on the icing although I also wanted to be sure of a good strong red colour.
For the cake itself I just used the first Battenberg recipe I found online, colouring all of the mixture with blue food colouring instead of separating it in two as you'd normally do. In order to maintain colouration I used water icing in place of apricot jam to glue everything together, and it did a great job; I attribute a good deal of the cake's stability to that. Also, bear in mind that with all the white stripes it takes about three times the amount of marzipan that a regular Battenberg does!
Again because of the short timescale, and also because it was a first try, I didn't worry about getting the width and placement of the diagonals exactly correct. It seemed unlikely anyone would fail to recognise what it was because of that!
If you do one of these yourself be sure to attract a crowd for the cutting of the first slice, that reveal and the reactions it generates are priceless!