When Bob Cockshott went to pick his 10-year-old son Alex up from school, he knew something was wrong.
The father-of-two couldn't pick out his son from the rest of the children in the crowd.
Since then, Cockshott has learned that after a stroke he gained a bizarre condition that leaves him to be unable to recognise the faces of his wife and two children.
Cockshott, 58, woke in the night fearing he had gone blind and doctors said he had suffered a minor stroke due to a blood clot on his brain.
He was discharged once the swelling on his brain had gone down with a slight loss of vision in part of his eye the only lasting problem.
But Cockshott realised his problem when he struggled to pick Alex out among a crowd of children.
And when he looked through family photo albums he found he couldn't recognise his own children when they were younger - or even a picture of himself.
He also had difficulty identifying Clare his wife of 22 years with her hair tied back in other photos.
Man Unable To Recognise His Wife And Children
Cockshott was diagnosed with a severe case of prosopagnosia - otherwise known as face blindness - which is a surprisingly common condition, but usually inherited.
Since then he has struggled to recognise friends and workmates but copes by memorising people's distinctive features, such as posture, mannerisms and speech.
He has decided to speak out about it now to raise awareness of the condition.
Cockshott, a director at the Knowledge Transfer Network - an initiative funded by the UK's national innovation agency - said: "When I used to pick my son up from school all the kids were in their uniform so I was unable to recognise him.
"There was a similar occasion at Charing Cross station with my daughter - she didn't tell me what she was wearing so I hadn't a clue who she was.
"I thought I only had a mild version of the condition but after I did some tests the doctors told me I had a severe impairment.
"It is very difficult to imagine really. People find it impossible to believe that I can't recognise their face.
"It is difficult for people I know to comprehend that my brain can't work out what they look like."
Cockshott, from Orpington, south east London, even looked at a picture of a couple holding a baby and didn't recognise it was him, his wife and their daughter.
He added: "It is only the faces that I can't recognise, so I can identify people by their hair or clothing or their mannerisms and posture.
"If there are people who look similar in the same place then I would really struggle. I wait for people to approach me.
"When I am in the supermarket my wife will whisper in my ear and say 'that's John our neighbour' or something like that.
"If a picture of my wife was in front of me and her hair was tied back I wouldn't be able to say who it was.
"There was one time when I was looking at a couple holding a baby and I recognised the baby's outfit but I didn't realise it was me and my wife holding it.
"Now the kids are grown up I can't really remember what they looked like when they were children."
Cockshott, who married Clare in 1993, is dad to son Alex, 17, and Anne, 13, and says they have all come to terms with his bizarre condition since his stroke in 2008.
Experts say prosopagnosia is not linked to problems with vision, memory or intelligence.
It is caused by an impairment in the right 'fusiform gyrus' of the brain - the area that appears to coordinate facial perception and memory.
It can be triggered by a stroke, traumatic brain injury or a neurodegenerative diseases but in most cases it is present from birth.
It is thought the condition affects as many as one in 50 people - about 1.5 million people in the UK - but the majority of cases are very mild.
Hazel Plastow, a director at Face Blind UK which Cockshott is a member of, said: "You can't cure face blindness but there are lots of strategies to help cope with it if we can raise some awareness.
"People certainly become more isolated because it is just too awkward and embarrassing to put themselves in certain social situations."