The new technology allows employers to be alerted via email when a hands-free kit is being used whilst the car is being driven – so they can take appropriate action.

Although technically the use of hands-free sets whilst driving is legal, drivers can be prosecuted under careless and dangerous driving laws if they drive poorly whilst distracted by a call – with companies also facing the risk of prosecution under the Corporate Manslaughter Act or the Health and Safety at Work Act.

Crystal Ball managing director Raj Singh said: 'Some companies have been very proactive in banning the use of hands-free kits for business-related calls, but until now this has been largely ineffective as they have not been able to monitor and enforce it.

'All companies receive itemised bills from their mobile phone network, however these are historic, don't record any incoming call data and do not record any journey data, so the bill is completely ineffective as a tool to enforce the policy.

'The new technology available through Crystal Ball means that employers can now, for the first time, be alerted when a hands-free kit or a hand-held phone is being used whilst the car is being driven and companies can then take appropriate disciplinary action.

'This allows companies to clearly demonstrate that they are being proactive in enforcing mobile phone policy and thereby potentially reducing their liability.'

The technology has been endorsed by former Det Chief Supt Mick Gradwell who said: 'This innovation is a great move forward in terms of companies monitoring safe driving policy.

'A hands-free kit does not cover you against the consequences of poor, careless or irresponsible driving whilst you are talking on the phone and companies also need to be aware of this and get the appropriate message across to their employees.'

The hands-free monitoring functionality is free until 31 December as part of comprehensive mobile phone and vehicle tracking packages available from Crystal Ball from only £6.94 per month. It is also available on a free trial.