Only six of the many thousands of "white fivers" produced in Portsmouth are known to have survived.

BBC: 'White fivers' raise a fortune

The common arguments against packing more fivers into cash machines included the greater cost to companies that sorted and supplied banknotes.

BBC: Five-pound notes are still a rare offering at cash machines

Why do foreigners want to join in the great British sport of hurling wads of fivers down this particular black hole?

ECONOMIST: Football