Celebrity ads do not work (with apologies to Jamie, Gary and Bob)

Whether it's Justin Timberlake scoffing a Big Mac or television DIY queen Linda Barker fronting a commercial for electrical store Curry's, it seems that no ad campaign these days is complete without its celebrity endorser.

Whether it's Justin Timberlake scoffing a Big Mac or television DIY queen Linda Barker fronting a commercial for electrical store Curry's, it seems that no ad campaign these days is complete without its celebrity endorser.

But now new research has concluded what many outside observers have long suspected: that celebrity advertising, in general, doesn't work.

The survey, to be published in a new book about the phenomenon, ironically titled Celebrity Sells, will make unpalatable reading for companies that have spent millions re-branding themselves around famous faces, and may sound the first distant toll for the cult of celebrity.

In-depth interviews with 300 members of the public revealed that celebrity adverts are, at best, viewed with complete indifference. One in five found celebrity ads "irritating". Even worse for those hoping their star-backed brands will stand out from the crowd, 37 per cent described them as "ordinary".

Only one in eight said they had ever been persuaded to try out a product or service because a star name endorsed it - the same number who said they had been swayed by non-celebrity adverts. More than half said that celebrity ads either didn't change their feelings one way or the other about the brands promoted or reduced their appeal.

Meanwhile, a separate survey by the Marketing Society has found that companies are in any case becomingwary of celebrities. Three-quarters of the 296 marketers asked said they were less likely to use famous faces to promote their brands than five years ago.

The author of the new book, Hamish Pringle, admits he was initially disappointed by the findings. Mr Pringle, the director general of the Institute of Practitioners in Advertising and a former vice-chairman of marketing at Saatchi and Saatchi, said he optimistically entitled it Celebrity Sells hoping this thesis would be reflected by the public's views.

"There's no evidence that celebrity campaigns are any more popular or have any more of an impact on sales than those that don't feature celebrities," he admitted. "Signing up a celebrity is not a recipe for success."

Nonetheless, Mr Pringle cites highly effective celebrity ads, including Jamie Oliver's campaign for Sainsbury's, which capitalises on the TV chef's "mockney" charm, and the long-running Walkers crisps commercials that overturned Gary Lineker's Mr Nice Guy image.

"Celebrity definitely does sell, but it doesn't sell in itself," Mr Pringle said. Among the less successful celebrity ads he cites are the recently scrapped Barclays campaign featuring Pulp Fiction star Samuel L Jackson, which has reputedly cost the bank up to £10m over the past two years. Also criticised are the Lotto ads starring Billy Connolly and Abbey National's short-lived campaign featuring former EastEnders star Martin Kemp.

Mr Pringle identifies four ways in which, far from being merely ineffective, the use of celebrities can actually "damage" the integrity or profile of a brand, including using an inappropriate celebrity. There can be legal problems too, as easyJet found recently when it used a picture of David Beckham without his permission to promote cheap flights.

Sometimes the star's personality obscures the product. The popular Cinzano ad in which Leonard Rossiter repeatedly spills his drink over Joan Collins were criticised at the time by advertising experts: viewers were too entertained to remember which drink was being promoted.

Then there's timing. Michael Jackson had just signed a multimillion-dollar contract with Pepsi when he found himself facing child abuse allegations. And O J Simpson's lucrative endorsement career foundered when he was caught on camera speeding away from police in an effort to skip bail on a double murder charge. At the time he was the face of Hertz car hire.

The stars who sold ...

The brand: Walkers
The celeb: Gary Lineker
The advert: Affable former England star in disguise steals crisps from fellow celebs, including Ulrika Johnsson
How it did: Lineker has wide appeal and Walkers is now the UK's number-one crisp brand

The brand: Barclaycard
The celeb: Rowan Atkinson
The advert: Bumbling British spy gets into trouble around the world but manages to pay for everything with his plastic
How it did: So engraved on the nation's psyche, the public thinks it's still running. Inspired a spin-off film, Johnny English.

The brand: BT
The celeb: Bob Hoskins
The advert: With his catch phrase "It's good to talk", the actor claimed he earned enough from the ads never to have to work again
How it did: BT successfully used Hoskins's hard man image to help it shift the perception that long chats on the phone were for girls

The brand: The police
The celebs: Lennox Lewis, John Barnes, Sir Bob Geldof
The advert: Celebs confess they lack the mental strength to be a police officer, prompting the public to wonder if they could do better
How it did: Portraying rock and sports figures as fallible, it contributed to a 52 per cent rise in recruitment enquiries

The brand: Sainsbury's
The celebrity: Jamie Oliver
The advert: "Mockney" chef Jamie marvels at the fresh food in the supermarket, before nipping home on his scooter to cook some "pukka" grub for his family and friends
How it did: The BBC dropped The Naked Chef, fearing viewers associated Oliver more with the supermarket. Sainsbury's claimed he added £1.2bn to the value of its brand

... and those who didn't

The brand: Abbey National
The celeb: Martin Kemp
The advert: Ditzy everywoman discovers her blind date is dishy Martin Kemp. Switching your mortgage to Abbey National could be equally delightful
How it did: Abbey dropped the ad and changed its name

The brand: Lotto
The celeb: Billy Connolly
The advert: Man of the people prances around with a purple beard imploring us not to live a little but "a Lotto!"
How it did: Sales continued to slide. Camelot ditched the comic and used "ordinary" folk The brand: Cinzano

The celebs: Leonard Rossiter and Joan Collins
The advert: Drooling, clumsy Rossiter looks at his watch and pours his drink over glamorous Collins
How it did: Let's face it, you thought it was for Martini

The brand: Barclays
The celeb: Samuel L Jackson
The advert: Pulp Fiction star saunters down country lanes spouting intellectual-sounding gibberish
How it did: Despite Jackson's enormous bankability, the adverts have been quietly discontinued

The brand: ITV Digital
The celebs: Johnny Vegas and his monkey
The advert: Northern comedian and show-stealing sidekick watch telly
How it did: Made stars of Vegas and Monkey,but ITV Digital collapsed in 2001

The brand: McDonald's
The celeb: Justin Timberlake
The advert: Former boyband star risks the little credibility his solo career has brought by backing fast-food giant
How it did: Too early to say

Steve Bloomfield and Hannah Forbes Black