I asked the shop assistant who served me in Marks and Spencers today if it was okay to pay her in cash. Quite rightly she looked bemused. Pounds and pence are still legal tender (at the time of writing), it is not the morals of the payer which should be called into question but the morals of the payee as it is their responsibility to make an accurate declaration of their income to HMRC each year. I think there are many 'moral' questions to be answered by society but this one is certainly nowhere near the top of the list!