The Advertising Standards Agency (ASA) banned the ad because Vauxhall did not clearly explain how the vehicle worked in “extended-range mode”, which according to the ASA meant that a combustion engine fuelled by petrol would start to power the car’s electric motor once the battery charge was exhausted.

Vauxhalls parent company, General Motors UK, responded to the claims saying that the car was capable of travelling up to 50 miles on a fully charged battery, and that beyond that point the Ampera’s “range extender” mode took over.

In this mode the internal combustion engine acted as an on-board generator for the electric motor and would take the car the remaining distance using electricity generated from the petrol in its fuel tank.

The ASA said it acknowledged that the ad contained on-screen text which referred to the car’s “additional power source”.

However, the agency said it “considered that the qualifier, even when an additional power source is generating electricity, was ambiguous, particularly in the context of an ad for a new type of hybrid car”.

It added that an average viewer unfamiliar with the use of petrol engines in electric vehicles would not necessarily understand what the additional power source was.

The agency said: “We considered that throughout the ad the emphasis was on the fact that the car was being driven electrically, and that most viewers would not understand that the car was in some circumstances being powered by electricity generated with a petrol engine.

“The ad promoted an innovative product which many viewers would not immediately understand and we therefore considered that it would need to explicitly state that the car had a petrol engine. Because it did not clearly explain how the vehicle worked in extended-range mode, we concluded that the ad was misleading”.

Leigh Stringer

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie