Police would save time and money if they got rid of live identity parades and showed witnesses a video line-up instead, according to new research.

The practice is fairer to non-white suspects and also costs less money, said Tim Valentine of Goldsmiths College, University of London.

Speaking at the British Association Festival of Science in Glasgow, the psychology professor said the fairness of identity parades had been measured for the first time.

The construction of video line-ups made them fairer for African-Caribbean suspects, he said, possibly because people from ethnic minorities were less willing to stand on parades.

"More of the volunteers for the videos are a better fit to the description that the witness gave, so there is less probability of picking someone purely by chance rather than from memory," he said.

Witness anxiety

Professor Valentine argues that the use of video avoids the need for a witness to be in the presence of the suspect, thus reducing witness anxiety.

It also saves money on paying volunteers for each parade and reduces the cost of parades that have to be cancelled because the suspect on bail fails to attend.

Professor Valentine has been working with West Yorkshire Police, who have been piloting a video system of identity parades since 1996.

Instead of a witness or victim turning up at a police station to look at a suspect and nine volunteers lined up next to each other, they get to look at a 20 second video line-up before making a decision.

The video shows a head-and-shoulder shot of the suspect together with eight or more images pulled from a video database.

Professor Valentine knows of 40 cases using this method that have led to convictions using video identifications.

In 1996, the cost of identity parades was �14m, with half of these cancelled at short notice, he said.

The Home Office is reviewing current codes of practice.