Susan Stranks, a presenter of the children's television programme Magpie in the 1970s, wants Pounds 44 million over four years from lottery funds, commercial partners and family trusts to fund children's radio on the spare 225 kHz frequency.
But Miss Stranks and her supporters, who founded Children 2000 in 1995 to focus lottery profits on children, are competing against rivals with interests in sport, news, music or talk radio stations.
"Listening is regarded as crucial for the development of concentration, imagination and communication and recent studies indicate that serious attention disorders can develop from poor auditory skills," she said. "One in five pre-school children suffers speech delay."
Children's BBC now only amounts to half-an-hour on Sunday evenings and last month saw the final daytime broadcast by school radio. Miss Stranks said: "In nearly 50 BBC and 180 independent radio stations, nothing is earmarked for children, who are simply left hostage to whichever chief executives happen into power."