The Vivaro 2700 panel van also took the Best Large Trades Van and the Best Green Van, while the Best Heavy Van went to the Vauxhall Movano Panel 3500 panel van.
Volkswagen Commercial Vehicles was presented with Best Finance & Service Package, while its Amarok won Best Pick up, and the Transporter Kombi took the Best Crew Van award.
Best Small Delivery Van went to the Ford Transit Courier 1.0-litre Ecoboost Trend, while the Best Small Trades Van award was taken by the Ford Transit Custom 2.2 TDCi Trend.
On sale for just over a year and built in the UK, the latest iteration of the Vivaro won in part for its array of refinements and the 1.6 CDTI 16-valve BiTurbo, which delivers 119bhp and 320Nm of torque – and 47.9mpg on the combined cycle.
Other winning features included the Vivaro's cabin, which doubles as a mobile office, and the 8.6m3 load space with Vauxhall’s FlexCargo load-through bulkhead.
“The Vivaro provides outstanding green credentials and a fantastic overall small business solution,” comments Dave Bowen, chairman of the judges and managing director of BT fleet.
“It is easy and car-like to drive, yet offers a hard working business tool that through sheer efficiency helps minimise its environmental impact.”