In its analysis, GeneWatch comments: "The figures cited by the Prime Minister are not based on the tracking of actual cases. Rather, they are based on a statistical estimate of the numbers of matches that may have occurred between crime scene DNA profiles and the DNA profiles of persons who were charged but not proceeded against or acquitted.
"Not only is the actual number of retained profiles from innocent people unknown, but it is unclear how the number of matches made with these profiles have been calculated, since the estimate does not correspond to specific individuals."
A match on the database does not guarantee a conviction, GeneWatch points out. Past Home Office estimates have said that half of all matches to the database lead to a detection (i.e. identification of a suspect), and half of all detections lead to a conviction. Even if Brown's 114
murderers database matches existed, based on the contemporary government figures 57 of them "would in all probability have got away" [and, as commenters have pointed out, 27.5 who didn't "get away" would have been found not guilty].
Furthermore, the annual report Brown drew his conclusions from also estimated that in more than a quarter of cases where crime scene DNA matched the database, the police were given a list of potential suspects because the profile was not complete.
Wallace said: "This claim [that 114 murderers would have probably walked away] is both ridiculous and entirely false. DNA matches are not solved crimes - many matches occur with victims and with passers-by, or are false matches. People are not stupid - they know that keeping their children's DNA when they've done nothing wrong is not helping to solve crimes."
GeneWatch does not oppose the existence of the the NDNAD, noting its usefulness for law enforcement. It has lobbied against its rapid expansion under the current government from about two million individuals in 2002/03 to around four million individuals in 2006/07. In that time the proportion of crimes solved by DNA profile evidence has remained around 0.35 per cent.
Gordon Brown's intervention in the debate seems timely, if hamfisted. The Grand Chamber of the European Court of Human Rights is expected to rule soon in the case of two Sheffield men who have never been convicted of a crime, but whose DNA profile is stored by the government.
Since the Criminal Justice and Police Act 2001 the database has been further expanded to included everyone over the age of ten who is arrested. If the unidentified men win their case it could mean that hundreds of thousands of profiles would have to be deleted. The Prime Minister's speech followed soon after a warning by a retiring chief constable in the Sunday Times that "murder, rape and child abuse investigations will be hampered" if the government loses the case.
You can read GeneWatch's full analysis here. ®