Steve Bryant, Vauxhall’s CV brand manager said: “We are taking the lead on Type Approval, we have briefed body builders on the rules and we want to show converters we can work with them.”

The legislation, which was phased in to cover chassis cab conversions from April 2013, could put 25% of small vehicle body building firms out of business, according to Ron Cocker, Type Approval manager at the Vehicle Builders and Repairers Association.

He said EWVTA would be a “bureaucratic nightmare” for specialist body builders that would place “a considerable burden on smaller companies”.

But he claimed the reduction in the number of converters would not  cut capacity in a sector where 20% of body builders make 80% of vehicles but that larger firms would move in to take up the slack and vehicle manufacturers increasingly offer ready-to-run conversions.

Bryant said conversions account for 35% of registrations in the 3.5-4.5- tonne commercial vehicle sector with the Movano providing the base for most Vauxhall conversions – half of which are tipper, boxside or dropside bodystyles.

He said Vauxhall was working with recognised converters to exploit the market opportunity and claimed the Movano provided an ideal base with chassis, crew or platform cabs available in front and rear-wheel drive.

He cited the EWVTA rules as the catalyst for Vauxhall to ramp up conversion business as the number of market players declined.

“We want to work with the converters who embrace the Type Approval rules,” he said.

He added: “Recognised conversions are developed where the volume doesn’t warrant  a core model.”

Core conversions, which are developed ex-factory, feature in Vauxhall’s main brochures and price guides, fully covered by manufacturer warranty and already approved to EWVTA. Vauxhall now offers a range of 56 Movano core conversions compared to just 13 of the previous generation model. Recognised conversions cover more specialist applications and for these vehicles the body builder matches the Vauxhall warranty.

The brand is working with 10 converters who offer products under the new EWVTA rules. Current conversions, which are approved by Vauxhall engineers at the brand’s Specialist Vehicle Centre at Millbrook, include a Bott racking vehicle, Cold Consortium fridge van, Ingimex Luton box body, dropsied and tipper, Maxi-Low Luton box body and TGS car transporter.

Recognised conversions in the pipeline are a Movano 4WD, parcel delivery van and a welfare vehicle.