Norfolk police say no convictions relying on evidence from a police officer involved in a hit-and-run accident are being re-examined despite him having suffered from amnesia. 

Roads and armed policing officer PC Karl Warren failed to stop or report the collision when he rammed a marked BMW X5 into the back of an Audi A1 driven by a woman on the A146 between Lowestoft and Beccles.

READ MORE: Hit-and-run police officer avoids charges...because he 'can't remember' crash

He claimed to have no memory of the crash and criminal and misconduct charges against him have been dropped after evidence that he was suffering from an episode of a rare condition called transient global amnesia (TGA).

Eastern Daily Press: The crash happened on the A146 Barnby Bends between Lowestoft and BecclesThe crash happened on the A146 Barnby Bends between Lowestoft and Beccles (Image: Newsquest)

One in eight people who experience TGA go on to have a recurrence. A police officer suffering memory loss raises questions about the reliability of evidence.

However, a spokesman for Norfolk Constabulary said it was not reviewing cases PC Warren has previously been involved in.

He is now working in an administrative “non-operational role” not dealing with the public and is not involved in criminal investigations.

The spokesman added: “We have no concerns about cases the officer has been involved in at this time and therefore we are not reviewing other cases."

Simon Nicholls, former director of Belmores Solicitors in Norwich, who is an authority on criminal cases, said TGA was very unusual but not unknown.

“Some years ago I represented someone who had precisely that and it was shown that, even though he wasn’t badly injured, the impact of an accident had just triggered this condition of short term memory loss,” he said.

Eastern Daily Press: Simon Nicholls worked for 43 years as a criminal defence solicitor in NorwichSimon Nicholls worked for 43 years as a criminal defence solicitor in Norwich (Image: Belmores Solicitors)

Mr Nicholls said the prosecution would have to disclose PC Warren's condition in any future cases involving him giving evidence but it was unlikely to affect past cases.

“It might be different if a client said 'I told the officer this and that happened but then he said he could not remember any of that'.

“It is something you’d have to look at on a case-by-case basis.”

READ MORE: How could amnesia wipe memory of hit-and-run police driver?

He said the decision to drop criminal charges against the officer would not have been taken without significant evidence.

“I don’t think the CPS would drop something lightly because they know everyone would be saying it’s just because he is a police officer,” he said.

“I suspect there is some really good evidence as to why the case was dropped. 

“The best evidence really is that he had a colleague sitting alongside him who reported it."