Each year in the UK, hundreds of thousands of pounds in cash is stolen and stained during robberies, due to the use of cash degredation systems that permanently mark the cash. If this stained cash then goes into circulation, criminals are allowed to profit from the proceeds of crime and are not deterred from committing further offences.
The Bank of England supports the work of the cash, security, and retail industries in fighting to deter cash robberies.
We advise that dye stained notes are probably stolen notes. Advice on what to do if you are offered a stained note can be obtained at 
http://www.banknotewatch.org.