The study is part of a diversity project involving the major broadcasters
Women are outnumbered two to one on British television, a study commissioned by Channel 4 has found.
More than three-quarters of contributors to news programmes were men, a study of 386 hours of TV over three weeks on six main channels found.
Women did occupy half the roles in soaps, reports the study to mark International Women's Day.
Sky News is having all its programmes presented and produced by women for the day.
Researcher Dr Guy Cumberbatch claims the study is the most comprehensive analysis ever of people appearing on television screens.
"Accusations of sexism and ageism on TV are not new," says BBC media correspondent Torin Douglas.
"But this research gives broadcasters figures to measure themselves against."