Do you struggle to identify your grandmother when she’s not wearing her trademark woolly hat, or ignore colleagues when you see them in town on a Saturday?

If so, you may have face blindness.

People with face blindness, or prosopagnosia, cannot recognise people by their facial features alone. It is thought that up to one in 50 people may have the condition, with sufferers including Brad Pitt and the businessman Duncan Bannatyne.

A team from Bournemouth University has drawn up the first framework to standardise early diagnosis. They found that families and friends may be better at spotting the condition than those who have it. It can be spotted in children as young as two, they said.

Their list of what to look for includes