The manufacturer will supply the fleet with 16,000 vans over the next three years in a deal worth more than £100 million at showroom prices.

It won the contract, with an option for a two-year extension, following a competitive tender process that included many of the major commercial vehicle manufacturers in the UK.

BT engineers will use the vans to perform their work all over the country and the group will run the vehicles on operating cycles of between one and five years, with the aim of optimising residual values at disposal time.

During the competitive tender process, BT Fleet held product evaluation events where BT engineers and managers test-drove vehicles from the shortlisted manufacturers.

Feedback gained from these testing sessions was one of the inputs to the adjudication process. BT operates what is thought to be the largest independently owned fleet in the country through its subsidiary BT Fleet, with 45,000 vehicles including 13,000 light vans, 16,300 medium and heavy vans and 11,200 cars.

As part of the new deal, BT will buy three models from Vauxhall – the 1.3CDTi Corsavan and Combo and the 1.9CDTi SWB standard roof Vivaro. BT head of fleet supply, Peter Howard, said wholelife costs was a key factor in the decision to award Vauxhall the contract.

He added: ‘The principal reason for our decision to switch to Vauxhall was the fact that their vehicles offered the best wholelife costs and will give us the best return over the contract period.’

All vans supplied will be fitted with racking and liveried in BT colours.