Ministers are reluctant to impose a ban but the National Heart Forum, an alliance of 50 groups, is seeking a judicial review in the High Court. The National Heart Forum launched its action after Ofcom refused to consider a 9pm watershed in its consultation exercise on food ads aimed at children.
Richard Watts, the co-ordinator of the Children's Food Bill campaign, said: "Ofcom seems to be umbilically linked to the TV and food industries, so it's no surprise it has bottled out of a proper consultation on protecting children."
The group has published a survey showing that 68 per cent of parents want a pre-watershed ban, while just 7 per cent are against one.
Ofcom concluded that such a ban would not meet its regulatory requirements and was therefore an inappropriate option on which to consult.
It has now asked interested parties, including the ad industry, to comment on whether the move would be "disproportionate".