The big sell: Branded products are the co-stars of more and more blockbuster films

It is the marketing man's Holy Grail and the cinemagoer's bête noire. Product placement, with beer bottles catching more on-screen time than the actors; clumsy references to characters' favourite brands; and car-chases that resemble TV adverts, is a multimillion pound industry.

Now blockbuster producers are being taken to task by a study that singles out the most blatant sell-outs. Marketing monitor Brandchannel, which has tracked product placement in big-budget films since 2001, is handing out some dubious accolades.

"People go to see a movie, not a bunch of adverts. There is a precarious balance, and some people have just whored out their films," said Jim Thompson of the US-based firm.

Perhaps unsurprisingly, Sex and the City was deemed to be the worst offender, and handed the Film Whore award by Brandchannel. The film, which declares in the opening scenes that life is all about "love and labels", features 25 fashion designers, eight shops, seven electronics brands, seven publications, seven food and drinks brands, five cosmetics companies, three car companies, and one airline.

Sex and the City director Michael King crammed a lot more into two hours and 20 minutes than most of this year's blockbusters, which were found to contain an average of 22.1 brands each.

Ford was also singled out, appearing in 57.7 per cent of the films that topped the US box office over the past year. The Ford Mustang that appeared in I am Legend was deemed to be top Scene Stealer for taking attention away from its human co-star Will Smith.

Rival car firm Audi was awarded Best Off-Screen Support for the way in which the firm exploited the R8's role in Iron Man in its off-screen advertising: the film's star Robert Downey Jr pulled up at premieres in an R8.

Brands will pay huge sums to get their products into the hottest films, figures that are a closely guarded secret. It is thought that the companies that will appear in the upcoming James Bond film Quantum of Solace, including Ford, Heineken and Sony, have invested £50m in the film's advertising campaign alone.

While studios argue that such sums are necessary to finance big-budget films, many directors and producers are less happy. "At best, it is an extraneous interference, at worst it really subverts the film," said British director Ken Loach. "It is something every director would be resisting."