The Flying Squad also wants all stained notes already in circulation to be withdrawn.
Supported by the Bank of England, the Squad has been working on the ‘Banknote Watch’ initiative for the last 12 months.
DC Alan Townsend, of the MPS Flying Squad, said the initiative was started to curb armed robberies. "If stained money is not so readily accepted," stressed Townsend, "then the incentive for committing robberies in the first place will be greatly reduced."