TomTom’s EcoPlus module plugs into the on-board diagnostics system and measures idling, fuel consumption, gear selection and engine revs while the standard black box has an accelerometer to measure braking, acceleration and cornering.

“A half laden Transit at 90mph will use twice as much fuel as at 70mph. Products like Active Driver give real time feedback about performance,” says Margerison.

Telematics tools can also offer a switch mode which records when a vehicle is being driven for business or private use.

“GPS fleet management customers have reported a reduction in overtime costs of up to a 54%, improved customer retention and fuel savings of almost £15,000 per year ,” says Joyce Tam, director of product marketing for Trimble’s Fleet Solutions.

“The typical payback for your fleet management hardware investment is three to six months.”

Top tips for choosing telematics

1 There has been a lot of industry fall-out, which can leave users with no service. Pick a financially stable company.

2 Decide on whether you want to buy or hire – including pay-as-you-go. Operating costs are all deductible as a business expense; capital expenditure will be written down over time.

3 Be wary of third-party credit agreements underpinning your investment; if your supplier fails, you will remain liable for the payments.

4 Know exactly what information will lead to savings, how you will act on it and who is responsible for doing so. Otherwise much of the benefit is likely to be lost.

5Look for a supplier which works with most wireless networks and which can integrate the telematics system with your existing applications.