What's the cause? Cash or the Banks

Before I begin, let me clarify that we do not deal in cash as a tax avoidance scheme.

However, I have noticed that cash, as a medium of payment, is drying up. I always find being paid in cash a bit of a hinderance as you either need to make a special trip to the bank, or if you put it in the petty cash tin, it seems to evaporate at an alarming rate.

Nonetheless, it has occurred to me that if cash is disappearing from the economy, then that is a bad thing. There are no publicised money supply figures for cash in circulation any longer, we just use M0 or M4, neither of which are reflective of the pound in the pocket/ under the bed. We need money for the economy to circulate and the multiplier to kick in effectively (for every £1 spent, £3.50 was traditionally generated down the line).

Are the real issues in the economy therefore attributed to the lack of cash, or are we still focused on the banks? I suspect that less cash is a symptom rather than a cause.

The great thing about cash is that it is an immediate payment and we could all do with a better cash-flow. Bring back the folding stuff, please.