Letter from Simon Kelner: Carnival hero could be a champion for M&S

Yesterday, the model Rosie Huntington-Whiteley was unveiled as the new face of Marks & Spencer in a multiple-million pound advertising campaign you will have difficulty avoiding over the autumn.

You can see why they chose the winsome Miss H-W. I suppose the clue is in the name: in the eyes of the creative people who put these campaigns together, she epitomises the solid, well-bred British values with which the store likes to be associated.

The adverts will be glossy, beautifully styled and, no doubt, pretty ubiquitous. And they'll do their bit to shift the M&S autumn collection. (They better had do well, because, even if you have your receipt, advertising agencies don't generally give you a refund if you're not satisfied.)

Now, I would like you to turn your eyes away from the shots of Rosie and focus on a much grittier image; the one used by all newspapers of the incident at the Notting Hill Carnival, when a young man has been stabbed and the alleged assailant is seen running away from the scene clutching a bloodstained knife. A brave passer-by sticks out a leg in an effort to trip up the young man with the knife. One of the aspects of this memorable picture is that our have-a-go hero is holding a Marks & Spencer shopping bag. Surely this (as yet unidentified) man is a more perfect poster boy for M&S than even Miss H-W. Public-spirited, courageous, decent: he may not have model looks, but he's a fine, upstanding member of the community who also knows good value when he sees it and that's why he shops at M&S! What's not to like?

The point is that, very often, the best sort of advertising is that which is not on posters or on TV. It's called product placement and, whether it is by accident or design, it's a very powerful selling tool. Companies fall over themselves to get their products on successful TV shows or in blockbuster films (for instance, how much is it worth to Aston Martin to be associated with James Bond? And Sex and the City 2 was little more than an advert for the Dubai Tourist Board).

One of the seminal books about advertising, written in the 1950s by Vance Packard, was called The Hidden Persuaders - and that about sums it up. We take these influences in subliminally. So, beware: you may think you're watching your favourite superhero, but really you're being sold something.