In the aisle of Tesco I stood like one thunderstruck. It was not the print of a man’s naked foot that took me aback, as it did Crusoe, but a tin of ‘Mandarin segments in juice’.

These days we get our entertainment where we can, and I had toyed with buying tinned goods against the next disruption of trade, as Margaret Thatcher had stocked up with 20 tins of fruit in 1974 against inflation.