Jowell's move is a boost for the Advertising Association's plans to extend self-regulation. But there was a sting in the tail, as ministers made clear their frustration that the industry has not yet agreed firm proposals.
The pressure will now be on the AA to produce a workable scheme.
Jowell said in a policy document that the Government was "keen to see further developments", which would build on the pre-vetting of TV and radio ads and draw on the experience of the Advertising Standards Authority. While European Union rules would require Ofcom to be formally in charge, this would not impede moves to a system of co-regulation.
The 325-page Bill, expected to become law by the autumn of next year, goes much further than expected by sweeping away many of Britain's media ownership rules. It will allow Rupert Murdoch to buy Channel 5 and non-EU media giants to acquire ITV and national radio commercial companies. A big shake-up of local radio is also on the cards.
Despite opposition from advertisers, the Bill clears the way for a merger between Carlton and Granada. But the Government said: "The competition authorities are best placed to consider the effects on the advertising market and they may well prevent the formation of a single ITV company for the time being on these grounds."