Cashstash
This holds one £20 note, although it is a tight fit. It would be better if it could hold two, or a £50. Having said that, have you ever tried to actually *use* a £50 note anywhere other than a bank? £20s are much more acceptable to the average vendor and therefore much more useful, especially in an emergency. Worth having one of these while cash is still widely accepted - though not everywhere - and still legal.