One-third of benefit claims checked by Edinburgh City Council are to be investigated further for potential fraud, as part of a pilot scheme using lie-detector technology.

Although awaiting a full report, the council said around 25 calls over the first two months of the scheme which started in October were considered suspect after being put through voice risk analysis software operated by specially trained staff.

The introduction of the lie detector by the Department of Work and Pensions came ahead of the council's own campaign reinforcing the message that benefit cheats will not be tolerated and that the public has a role in helping to catch those who illegally claim taxpayers' money.

One Edinburgh resident was recently sentenced to 150 hours community service for claiming benefit of more than £11,000 over five years while she was employed.

Yesterday results for earlier lie-detector tests, which began last April in England, showed council tax payers saved £336,711.

Harrow Council, in north-west London, joined the project. It said 998 people were assessed in Harrow using the technology during a seven-month period and 119 (12%) were identified as "high risk".

Of those, 43 (4.3% of the total assessed) were found to have been paid incorrect benefit.

Voice risk analysis has been used in the insurance industry for more than five years and works by detecting changes in people's voice patterns such as hesitation or avoiding direct questions.

Patterns are calibrated at the start of the conversation by asking basic personal details such as name, address and date of birth. The system then flags up any discrepancies from this base stress level.

A spokesman for Edinburgh City Council said: "The vast majority of people who receive benefits are genuinely entitled to them. However, there is a minority who are intent on stealing money from those who need it most."