Police interviews with suspects and witnesses will be captured on video in future, so juries can see as well as hear what they're saying to detectives.

The move, due to be implemented at the end of June, is part of sweeping reforms to the Police service under the Police and Criminal Evidence Act (PACE.)

Passed by Parliament in December 2005, the act has already seen old-style identification parades replaced by new video parades employing computer images.

High-tech fingerprinting machines have also been brought in to replace the old "ink and roller" method. These allow the better quality prints to be stored as digital files.

The next move will be replacing tape-recorded Police interviews with video recordings. According to PACE implementation manager Mark Crampton, this is something backed by prosecutors and defence lawyers alike for the positive effect it will have on trials by jury.

"There are a number of obvious advantages, because at the moment all we have is a verbal account we can't see the expressions on someone's face and how they react to a question," he explained.

"It will also make it clear who makes a comment, because sometimes if there's a lot of people in the interview, it's not always clear."

Mr. Crampton, a former British Chief Inspector, added: "It's going to add a lot of credibility to what a witness' first account is. We won't use this for all witnesses but if it's a very complex or detailed investigation we would consider it for key witnesses."

The videos will have a clock counting each second, and are tamper-proof so they can't be edited, stressed Mr. Crampton. All breaks in the taping will have to be accounted for by the interviewers so there's less capacity for defendants to claim they were bribed or threatened during pauses.

Police stations and courtrooms are currently being fitted with the new technology, which may also be used in future to allow vulnerable witnesses and prisoners on remand to appear in court via videolink.