Phil Horton, the marketing director at BMW, said there was a link between the general standard of TV advertising and the fall in audiences.
"In the UK, we've always claimed smugly to have the best advertising in the world, but how much are we, the advertisers, and our agencies responsible for low ad attention, zapping and wallpaper breaks?" he asked.
Horton also called on clients to shoulder some of the blame that has traditionally been laid solely at the feet of the broadcasters.
Stephen Woodford, the chief executive of WCRS and president of the IPA, talked about TV being the most powerful medium available to advertisers.
"Major steps have been made in this area and today's excellent event is another indication of this," he said. However, he added: "There is a strong legacy of arrogance from the past - creative agencies are not treated very well. We now spend a lot of time thinking of creative ways not to use TV."
And the ad industry was warned to shake itself out of the complacent belief that the ban on tobacco promotion would protect it against further attacks on its freedoms.
David Kershaw, the Advertising Association chairman, told the conference: "One day, whether it be toys, cars, petrol, processed food or virtually anything, the danger of restriction, or even ban, is real and the effect on advertiser-supported TV horrible."
And the M&C Saatchi founding partner called for groups representing all parts of the industry to mobilise and safeguard categories vulnerable to attack, such as the advertising of food to children on TV. "To believe that the UK will be untouched by this tide is both naive and dangerous," he declared.
Speaking elsewhere at the conference, Dawn Airey, the managing director of Sky Networks, accused the BBC of distorting the TV market. In particular, she singled out its two digital children's channels, CBBC and CBeebies.
"When will the BBC get back in its bloody box?" she said. "The children's market is superserved."