His Wonderbra campaign used Britain's billboards to offend and titillate the nation's motorists, while the fcuk moniker he created for French Connection attracted equal amounts of applause and indignation on the high street.

Now Trevor Beattie is turning to the internet after quitting the agency that made him the most famous creative executive in British advertising. The architect of New Labour's election advertising is launching an internet campaign for French Connection at his new firm, Beattie McGuinness Bungay.

The fashion chain is going online in an attempt to reverse a sales slump that forced it to issue a profits warning this month. Internet advertising is becoming increasingly popular with companies chasing younger customers who are diverting their attention from television to mobile phones and new media.

Users of the Yahoo! instant messenger service, who can swap messages while online, will be able to browse French Connection's summer collection and then view the clothes on a virtual model.

The online mannequin, known as an avatar or virtual person, is also designed by the user and will appear next to the instant messenger box. If internet users like what they see, they can then click on the retailer's website to make a purchase.

"We wanted to do something that conquered uncharted territory, to do something that no one had ever done before," said Mr Beattie. "It's time for fcuk to conquer cyberspace."

Mr Beattie set up his new agency after surprising the advertising world with his abrupt resignation as chairman of TBWA/London in May.

As with most new advertising outfits, BMB is keen to emphasise its difference. The new company is interested in content, possibly as a means of working brands into films and TV shows, and is working with Matthew Vaughn, the film director who made Layer Cake.

BMB's fledgling client list includes Sky News, which hired the firm to work on its £20m relaunch later this year.