Ed Richards, the Ofcom chief executive, has defended the new wide-ranging restrictions on junk food advertising to children, claiming they will cost the TV industry £210m less than a total ban.
Ofcom has been attacked from all sides following today's announcement.
Broadcasters are arguing that the restrictions are too draconian and that the output of children's programming could be affected.
Health campaigners have complained that the restrictions are too soft and have renewed their calls for a complete pre-watershed ban on all junk food advertising before 9pm.
Richard Watt, campaign co-ordinator at Sustain, said that it had not ruled out calling for a judicial review in a bid to win a pre-watershed ban.
Mr Richards argued that health campaigners did not understand how effective a new index - intended to determine which programmes had "particular appeal" to under-16s and should be included in the junk food ad ban - would be.
"I am not surprised health groups don't understand, but broadcasters are familiar with how to apply the index and to make a judgement on a programme's appeal to children. They have used the technique in relation to gambling and alcohol," said Mr Richards.
"The restrictions are the best way of targeting intervention of these ads at children. The consequences of a blanket ban on the budgets of broadcasters is extremely large indeed - in excess of £250m. That is disproportionate and we have to balance that to ensure we have high quality programmes across the UK."
Ofcom intends to review the effectiveness and scope of the new restrictions in autumn 2008, one year after the full implementation of the new content rules.
Health groups have also argued that the rules are potentially "fatally flawed" because they do not apply to brand advertising. This meant that a junk food company could still advertise to children if only its brand, rather than a product, was displayed.
However, Ofcom has said today that while brand advertising would be allowed, it "will look to advertisers to act responsibly in their wider interpretation of, and response to, the measures to restrict HFSS [food high in fat, salt and sugar] advertising."
If advertisers chose to use brand advertising to "seek to avoid product-based restrictions", Ofcom would scrutinise this area in its review in 2008.
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