The Whole Truth
A key witness at most murder trials is the scientific detective - the explosives expert or the pathologist who's done the post mortem on the body.
The expert evidence is often the decisive factor in deciding guilt or innocence. But how impartial are the experts? Does the present legal system make it hard for them to tell the whole truth? Are the experts just making a case for the defence or prosecution? One eminent QC tells Panorama : ' A criminal trial is not an objective search for the truth'.
Margaret Jay reports on the doubts surrounding scientific evidence and looks at the case of people convicted on the word of unreliable experts.
Producer CHRIS OXLEY
Deputy editor ANDREW CLAYTON Editor GEORGE CAREY