It may be good to talk, but latest research for BT has shown that the more it spends on advertising, the more negative its public profile. Which is why those watching TV over Christmas and the New Year will have seen the telephone giant perfecting a new public face - meticulously in tune with the caring, sharing Nineties.

"Social responsibility" is the latest marketing wheeze. Businesses and organisations - from Tesco to the Co-Operative Bank - urge us not only to buy their goods and services, but like and respect their values, too. The new commercials feature a sequence of apparently unrelated images of people and experiences, such as a wedding party and a small boy listening to his pregnant mother's swollen tummy. At first glance it could be an ad for anything. Hanson, maybe, or Midland Bank. But no, it's for one of Britain's largest advertisers: BT - a company better known for persuading us to spend more time (and money) on the phone than caring about others. Its aim? To position itself as a responsible corporate citizen.

"It is BT's view that corporate reputation will be increasingly important in the future," says Jeremy Miles, group account director at BT's advertising agency. "Already, it is a feature which distinguishes BT from other telecoms operators." Trouble is, no-one knows it.

According to Jackie Kavanagh, head of corporate campaigns at BT: "People increasingly expect companies to play a more active role in society." Aside from charitable donations, BT has worked with local communities on a range of economic regeneration initiatives, she claims - not to mention job creation and schools support. "The time is coming when good products and services alone just won't be enough."

BT has a number of different strands to its gargantuan advertising campaign, Miles explains. There are ads to encourage us to phone abroad and ads to woo small businesses. Then there are ads to promote its numerous discount packages - like Friends and Family, for which a new commercial featuring former cast members from EastEnders broke last Monday. Previous stars, including the faces behind Dirty Den, Arthur, Sharon and Michelle, arrange a reunion. And, perhaps most memorably, there are ads to encourage us `It's good to talk'. The company even funded its own TV programme to promote better telephone communication - the show, Now We're Talking hosted by Philip Schofield, went out on ITV a fortnight ago.

The new social responsibility campaign, however, is something else. Internal research for BT suggests people are beginning to get fed up with BT ads. And small wonder: latest industry estimates suggest the company spends more than pounds 150m on advertising each year. The good causes push may cost a mere snip at pounds 2m, but BT sees it as a critical investment - to stem a negative trend before it really catches on.

Anecdotal evidence suggests widespread surprise at BT's change in advertising tack, according to Miles. As for whether it's achieving the desired effect - well, it's just too soon to say. However, companies like BT eager to raise the profile of their corporate conscience have to tread carefully. For while the Nineties consumer expects businesses to accept a degree of social, community or environmental responsibility, they also increasingly treat any advertising or marketing communication with a generous dose of healthy scepticism.

BT's size and market dominance is a particular obstacle which must be overcome, it seems. Does such an obvious market leader really need to advertise so heavily? Jo Smith, a 27 year-old PA working in Finchleyf, North London thinks not. "If it's such a good corporate citizen, why doesn't it spend less on advertising and cut the cost of calls," she asks.

BT's claims it must advertise heavily to protect its business from growing competition. Recent research conducted for the company shows the British talk one-third less on the phone than their US counterparts - so there's still plenty of room for growth, it adds.

However Steve Carpenter, 30, a management consultant from Rugby is not entirely convinced. BT's involvement in Now We're Talking was to champion the art of conversation and encourage more effective communication, he points out. "Fine sentiments," he comments. "But is it really much more than just another way to get consumers to spend more?"