The Government's long-awaited Communications Bill, which was published on Wednesday, makes no specific reference to last month's pledge by ministers to consider devolving control of broadcast advertising to a new body similar to the Advertising Standards Authority.
The mammoth 844-page Bill proposes that TV and radio ads would come under the remit of Ofcom, the new super-regulator for the communications industry to be set up by the legislation.
The Advertising Association was eagerly awaiting the publication of the Bill to see whether ministers put the self-regulation plan "in black and white", and was disappointed to see no firm proposal.
Industry figures have been worried by conflicting signals from the Government over whether it will bring broadcasting into line with print. Their hopes rose last month when ministers said self-regulatory bodies could play an important role in helping Ofcom to achieve its objectives.
The Department of Culture, Media and Sport denied that the Government was going cold on self-regulation, insisting that a key principle of the Bill was "self-regulation where appropriate". A spokeswoman said: "We are not moving to self-regulation for broadcasting at this moment. But Ofcom will be able to review the system and decide whether there can be a more self-regulatory system."
However, the omission of a firm plan may reflect doubts among ministers about whether the advertising and broadcasting industries could reach agreement on the issue. Ministers have challenged them to produce a workable system.
Although the Bill could be amended during its passage through Parliament, ministers are likely to defer a decision on broadcast regulation until the Ofcom review, which could be two or three years away.
Andrew Brown, the AA's director-general, said he was "disappointed" that the plan was not mentioned in the Bill, which was "a bit odd" given the Government's positive statement about self-regulation last month.
The Bill does extend the current ban on political advertising on TV and radio despite fears that it might breach the free speech provisions of the European Convention on Human Rights. Tessa Jowell, the culture secretary, said: "This is an important plank in protecting the impartiality of broadcasting and democratic debate."