Don't know if this has been covered previously, but just as a bit of fun...
Which unit of the British Army had the largest cap badge? - HPs obviously not included
I have read that it was the City of London (Rough Riders) KK1359/KK1360, which measures about H = 57mm x W = 45mm, but do not know if this is correct.
RoRid.jpg
Some Scottish units have big ol' badges too; the London Scottish, being approx H = 49mm x W = 53mm (KK1840/KK1841)
LoSco.jpg
Are there bigger?
Regadrs,
Peter