Secret plans by the Government to use lie detectors to weed out fraudulent benefit and compensation claims were last night condemned as an invasion of privacy.
Ministers are examining whether to adopt a controversial technique recently adopted by insurance companies to catch bogus claimants.
Government documents obtained by The Independent show both the Department of Trade and Industry (DTI) and the Department for Work and Pensions (DWP) are considering proposals to monitor telephone calls from the public to detect signs of stress in the voice that can betray false claims.
The move was condemned by opposition MPs, who attacked lie detector technology as unreliable and said it was no basis for determining the honesty of claimants.
DTI documents have privately acknowledged that using the technology could be "presentationally very sensitive" and should be kept secret for the moment.
The plan has been drawn up by DTI civil servants handling a scheme awarding compensation to miners who suffer vibration white finger, which is caused by working with chainsaws and drills.
The biggest scheme of its kind in the world, a large backlog in dealing with claims from former miners and their families has built up. About 600 cases of suspected fraud are being investigated by an insurance company employed by the DTI to assess the claims.
A memo to Nigel Griffiths, a trade and industry minister, says: "Using this technology is likely to be presentationally very sensitive if, after the pilot, we do go ahead. However, we think it is worth looking into it."
It discloses that the DWP is also looking at the same technology, but tells ministers that if the lie detector technique is used "it will be the first time this method is put into practice in the private sector".
It urges ministers to hold a pilot in absolute secrecy and not to tell solicitors who are representing claimants.
Mr Griffiths is understood to be strongly resisting the proposal, while the DWP denied that it was considering using the technology. A spokesman said the department "has no plans" to use lie detectors. The technology could be used both for miners who make claims and their families and helpers.
But Steve Webb, the Liberal Democrats' work and pensions spokesman, expressed concern abut the technology's use in the benefits system. He said: "These things are black boxes. How can you appeal against the decision of a black box? People's cases should be determined on the individual facts."Reuse content