Professor Dingwall said it was easy to mistake the concentration of alcohol to other substances when making hand sanitiser, which could damage skin and pose safety risks.

“There is also a risk you put it on and then turn on a gas tap and then your hand goes up like a Christmas pudding,” he said.

Professor Dingwall said thorough, regular hand-washing was even more effective than store-bought hand sanitiser – and that the average person should be washing their hands six-to-nine times daily.

“We need to re-enforce the message to wash hands as soon as you come into your house and have been holding hand rails on the bus, used the toilet and eaten food,” he said.