Cornwall Council cabinet member Fiona Ferguson has quit over what she claims are plans to use 'lie detectors' to root out benefit cheats.

The voice “Voice Risk Analysis” (VRA) techniques will be used to assess people who, under law, have a single person discount on their council tax.

The 'lie detectors', are part of a review of claimants carried out by Capita, which has also sent letters to all those who receive the reduction on their bills.

The technology, which according to Capita, is "capable of identifying stress and emotion in a caller's voice pattern", has been broadly rubbished.

A trail by the Department of Work and Pensions (DWP) in 24 local authorities found: "From our findings, it is not possible to demonstrate that VRA works effectively and consistently in the benefits environment. The evidence is not compelling enough to recommend the use of VRA within DWP." with suggestions that there is no evidence that it works."

The contract will cost the taxpayer about £50,000.

Mrs Ferguson said the use of the technology would be "extremely damaging to our reputation".

She claimed that the leader of the council, Jim Currie said she would be ‘sacked’ if she informed members that this software will be used.

Adding, in her letter to Mr Currie: "That will not be necessary. Please accept my resignation with immediate effect."

Mrs Ferguson's resignation letter is printed in full below.

As you know, it came to my attention that the contract let to Capita (before I took up my portfolio duties) to survey claimants of the single person’s council tax relief will include the use of “Voice Risk Analysis” (VRA) techniques when making phone calls to claimants.

These techniques are sometimes called “lie detector” tests.

It is clearly right that Cornwall Council takes a strong line against people who deliberately mis-claim tax benefits but in this case I am more concerned about the impact on the vast majority of honest claimants.

In passing, although this does not deal with my fundamental ethical objection, I note that the techniques used by Capita were trialled by the Department of Work and Pensions in 24 local authorities on the processing of Housing Benefit between August 2008 and December 2010.

Their report issued in September 2010 said: “From our findings it is not possible to demonstrate that VRA works effectively and consistently in the benefits environment. The evidence is not compelling enough to recommend the use of VRA within DWP.”

I have discussed this matter with the Monitoring Officer. He has advised me that, as this is an operational matter in relation to a contract that the Council has already entered into, he strongly advises me that I should not require that this software is not used. If, contrary to his advice, I maintain my stance that we must not use this software then officers will comply provided you also agree.

You have made it clear to me that you will not agree. Indeed, you have said that I will be ‘sacked’ if I inform members that this software will be used.

That will not be necessary. Please accept my resignation with immediate effect.

May I say that I have no reason whatsoever to believe that you were aware of this aspect of the contract before I drew it to your attention. I also appreciate that you are in a difficult position in view of the Monitoring Officer’s advice. But, I do not believe that his advice is correct and I cannot accept it on ethical grounds. I also do not believe that it will help the Council to pursue fraud (which we must surely do) if the public think we are using this software. Finally, I fear that it will be extremely damaging to our reputation.

Therefore, I am launching a petition to require any use of this type of technology to be approved by Full Council.