A children's charity has called for a ban on "ruthless and exploitative" advertising directed at youngsters.

A poll by the Children's Society found almost nine in 10 (89%) adults believe children are more materialistic than previous generations.

Doctors are also concerned children's preoccupation with the latest trends could lead to mental health problems.

The Good Childhood report, which accompanied the poll, found: "Advertising to children was ruthless and exploitative and they should not be viewed as small consumers, particularly for younger children with impressionable minds."

Bob Reitemeier, chief executive of the charity, said: "If an advert is described as ruthless it is clearly inappropriate and raises questions about how we value children. These ads should be banned.

"Children either purchase or have an important influence on purchases worth £30bn a year. That's a big market."

The Archbishop of Canterbury, Dr Rowan Williams, patron of the inquiry, said: "The selling of lifestyles to children creates a culture of material competitiveness and promotes acquisitive individualism at the expense of the principles of community and co-operation."

Professor Philip Graham, professor of child psychiatry at the Institute of Child Health, London, who is leading the charity's inquiry into children's lifestyles, said: "One factor that may be leading to rising mental health problems is the increasing degree to which children and young people are preoccupied with possessions - the latest in fashionable clothes and electronic equipment."

But Baroness Buscombe, chief executive of the Advertising Association, said: "Calls for advertising bans are ill-considered. Such simplistic calls have no basis in evidence and restrictions would have unintended consequences.

"In Sweden, the ban on advertising to children under 12 has been in place since 1991 but, as the government's Foresight Report website demonstrates, there is no clear evidence of its efficacy."