The technology offers the prospect that someone phoning in for a sickie on Monday morning will speak not to a sympathetic secretary, but  to a computer set up to check whether their voice is steady and reliable.

One trial in Harrow, North London, saved the borough £420,000 in false benefit claims.

The Harrow system, developed by Capita and Digilog UK, is called Voice Risk Analysis. It is designed to make thousands of checks on a voice during a call.

If it picks up changes in a caller's voice that suggest they are under pressure - as is likely to happen if they are lying - it gives prompts to the operator, secretary or manager taking the call.

They can then encourage the caller to change their mind about being sick.

Lawrence Knowles, managing director of software and outsourcing firm Midland HR said that the system would soon be a useful tool in reducing sickness absence.