Viezu claimed the programme, which began in late-August, will see it remap 20,000 of BT’s light commercials to improve fuel consumption, cut CO2 emissions and enhance drive quality.

Steve Watson, BT Fleet’s senior innovation and design specialist, said that, as well as bolstering the company’s environmental credentials, the arrangement made sound economic sense.

“We crunched the numbers and the business case stacked up,” he said.

The vans covered in the initiative range from car-derived vans such as Vauxhall Corsavans to Ford Transit chassis cabs.

Adjustments to the vehicles include throttle, rev, speed and power limiting and BT Fleet has anticipated that the scheme will result in savings of at least £3 million. Viezu boss Paul Busby said: “Vehicle remapping offers fleets a host of opportunities and we’re being increasingly asked by companies like BT to help them achieve their environmental and reduction targets.”

He claimed fleets could see a payback on their investment in remapping within three months.

The programme covering BT’s 24,000 vehicles is set to be completed within four months.

The remapping is being carried out at BT Fleet’s 63 garages across the UK as vans come in for MoTs and servicing.