TRUST is vital in any relationship - including the relationship between a consumer and a manufacturer.

The German car giant Volkswagen Group has discovered this to its cost during the past month as the scale of diesel emissions cheating emerged.

In the UK alone, 1.2 million cars Volkswagen, Audi, Seat, and Skoda cars are set to be recalled while in Scotland, law firms are gearing up to take VW to court after being inundated with calls from Scottish motorists furious at being conned.

The first affected models are believed to have entered the UK market back in 2008.

I have seen no shortage of comments from people criticising owners of the affected Volkswagen Group brands for "cashing in" by pursuing compensation over the deceit, with worse levelled at "ambulance-chasing" lawyers.

Of course there is an element of that - but money is also the only language multinational corporations understand. Without the fear of adverse publicity pummelling their share price or lawsuits costing billion of pounds in damages and fines, how else do you deter other manufacturers from attempting to pull the wool over customers' and regulators' eyes in future?

Executive heads have rolled already, although VW insists that no one in senior management knew of or authorised the use of so-called defeat devices. The scandal is shaping up to be laid at the door of a handful of "rogue engineers".

So far, VW's own internal investigation has seen three unnamed employees suspended.

A week ago, Michal Horn, chief executive of Volkswagen in the US, told Congress: "What I've learned is some people have made the wrong decisions to get away with something that wouldn't be found out."

In the end it was only the chance discovery by US automotive engineer, John German, of anomalies in emissions rates during lab and on-road testing which finally forced the car giant to come clean.

In true David and Goliath style, German's non-profit research organisation, the International Council on Clean Transportation, with an annual budget of just $12 million (£7.9m), has exposed one of the world's biggest corporate scandals.

However, Will Quince, a member of the House of Commons' Transport Committee, suggested that industry watchdogs had also dropped the ball.

He said: “The public are asking: ‘If we can’t trust car companies on emissions can we trust them on safety?’

“People put a huge amount of faith in regulators to protect them. The scandal has shattered trust and people are questioning what they can believe."

Environmental campaigners Greenpeace accused the independence of the Vehicle Certification Agency, the UK government body responsible for testing emissions in new cars, of a conflict of interest after revealing that the VCA has received £84m in the last decade from the same car-makers whose vehicles it is tasked to check.

In Europe, VCA competes against other member states’ agencies for the lucrative business of checking pollution levels in new car models before they go on sale and has claimed to be “the chosen supplier of type-approval services to most major global auto manufacturers".

The Department for Transport said the system offered "value for taxpayers".

Unhappy VW owners might beg to disagree.