The introduction of decimal currency was a massive logistical excercise that involved the secret delivery of 600,000,000 coins and 150,000,000 banknotes across the country to the nation's banks.
The task began on 29/11/1965 and was completed on 3/2/1966, eleven days ahead of C-Day. (Changeover Day).
The changeover inspired a decimal collecting industry. And further stimulated the collecting of pre-decimal currency.