Having watched a piece on BBC 1's 'Click' programme this morning I think it might be time to start stockpiling after all. They had a debit card on which can read your thumb print. You place your thumb on at 5 different angles so it can build up a picture, and then you're good to go. It is anticipated that this will be so secure that they will be able to lift spending limits on these cards, which automatically does away with the need to carry cash.