When I lived in France many years ago, I used to learn both French and marketing from the slogans of TV ads. They were the perfect source of bitesize wisdom. Three lines remain with me to this day.

– Perrier: l’eau, l’aire, la vie. I was totally in awe of the courage of a brand to stand not just for the meaning of water, but also claim part of the meaning of life itself.

– Carte Noir is France’s premium coffee brand and its slogan – Carte Noir – un café nommé desir – was so romantic and exciting, and reminiscent of Tennessee Williams’ Streetcar, that I was totally sold.

– Then there was Darty, France’s leading electrical retailer, which simply asserted their core values in their slogan: Darty – le contrat de confiance, or Darty – your contract of trust.

I have often thought the marketing heads in Darty were really switched on, as they got to the essence of why we buy brands at all.

Celebrities are brands at the centre of today’s marketing stage. As consumers, we are in control of their destiny. The price of being beloved is to be beholden. We may choose to have our famous folk return for endless encores (Bruce Forsyth; Eli Wallach) or we may despatch them to the gallows (Mel Gibson, almost; OJ Simpson, assuredly).

Behind every celebrity is a contract of trust with us, the audience. When trust is broken, meteors rain from the skies, and chaos ensues.

The disastrous events of Valentine’s Day 2013 in an upmarket suburb of Pretoria are primarily a great tragedy. A talented and beautiful woman lies dead and Oscar Pistorius stands accused of her murder. If you will excuse my vulgarity, I can also view this event as a brand implosion on a global scale. Brands have a certain elasticity, until the contract is broken.

Pistorius, as a celebrity brand, was deeply intoxicating to millions precisely because the maths simply did not work.

How could a man offered so little chance in birth make so much of his lot? How could he excel at running, the very thing that nature itself seemed to forbid? How could such a person turn out to be so redolently eloquent? And, a crowning glory, how in God’s name could he be so smokin’ hot?

Pistorius is now a man accused by the courts of murder, and by his fans of murdering dreams. All trust is broken. His brand is soiled, torn. Forgiveness does not go this far.

Of course, most marketing challenges do not entail murder and mayhem. But brands do have the ability to corrupt our environment, invade our bodies and even threaten our loved ones. Think BP and oil spills; Tesco and horse meat; Nestlé and baby milk….

Oscar Pistorius’ predicament is a human tragedy. It is also a dramatic example of a marketing truism. In creating brands, a contract of trust exists, whether we choose to recognise it, or not. Play rough with trust, and one may be the chief architect of an inglorious end.