As the deadline passed at the end of last week for comment on the government's media ownership proposals, there was a scramble among media companies either to get their papers in on time, or secure an extension. Rupert Murdoch's News International was one of latter.

Ministers might think this brinkmanship a bit rich, given the constant sniping they get from the industry about the slow progress of planned communications legislation. It is a sign that we are now entering the endgame: devising the rules which will determine who can merge with whom when the bill becomes law next year.

It will be a little time before it is possible to see the whole map of rival corporate interest, though we should learn more today when the leaders of ITV, Channel 5 and BSkyB are paraded before Gerald Kaufman's Select Committee on Culture, Media and Sport.

I trust there will be no need for orange uniforms, ear muffs and blackened goggles, but MPs had better be ready for some kicking and scratching.

For it is now clear is that the broadcasters have, once again, ganged up on Rupert Murdoch. At the time of the last Broadcasting Act, this stitch-up took the form of getting the government to agree strict limits on the ability of newspaper companies to buy into terrestrial TV. This so-called 20:20 rule had the effect of stymying only two groups: News International and the Mirror. Since the Mirror was a faltering company under poor management, it was obvious that the real target was Murdoch.

So with the latest proposals, advanced forthrightly by the BBC and Channel 4 in their response to the government's consultation document, but with some support from ITV.

They argue that the new cross-media ownership restrictions should cover not only links between television, radio and newspaper companies, but that a fourth media market should be identified: namely the provision of communications platforms.

In principle, this strikes at the cable companies, NTL and Telewest, and at BT, though at present none of these is a significant player in television content, let alone radio or newspapers. The target is Murdoch and his 36 per cent owned satellite company BSkyB. No wonder his executives wanted a couple of extra days' thinking time.

Apart from causing rage in the Murdoch camp, this proposal also flies in the face of a key assumption in the government's own consultation document on media ownership. This made the case for open and fairly priced access to all communications platforms, but explicitly pledged that "we will not impose ownership limits".

The logic of the government's position then was that fair access to communications platforms is, essentially, an economic matter and one which Britain's recently enhanced competition laws are capable of securing. The fact that the Office of Fair Trading already has a major case in progress against BSkyB is taken as evidence of this point.

What the broadcasters are saying is that this defence is inadequate; that competition policy works too slowly and retrospectively, by which time a content company could be severely damaged by lack of reasonable access to a key broadcasting platform. Arbitrating on this looks like a big test of the government's de-regulatory credentials.

What else can be discerned amid the din of clashing interests? There has been little industry support for the idea of cross-media ownership limits based on total share of voice. Intellectually convincing, but too complex in practice is the verdict. In my view, this remains the right system for the medium term and it would be advisable to start piloting it now, without giving it legal force.

Nor has there been much enthusiasm for the government's preferred route: to establish a new set of numerical benchmarks, which would allow any media company to control up to 40 per cent of a single market, 30 per cent of two markets or 20 per cent of three markets.

An even simpler variation, advanced by the Radio Authority, is that in any market, there should be at least three players, plus the BBC. The problem with this is that it says nothing about the newspaper market - source of most of the angst, since securing diversity and plurality in news provision is the most important aspect of the case for regulating cross media ownership in the first place.

The 40:30:20 rule would, if adopted, also cause difficulty for the Murdoch group, which controls over 35 per cent of the national newspaper market and so, theoretically, could be forced out of the television market altogether. If Sky's satellite platform is also to be considered a market in its own right, the restriction becomes even tighter.

Among the organisations expressing some support for 40:30:20 is the BBC, though naturally the BBC thinks that it should be excluded from these restrictions, on the grounds that it would be perverse to supply public funds to an organisation to provide an alternative to commercial broadcasting and then hold it back.

Actually, there is a good case for setting boundaries around the BBC if other players are not to be crowded out. It already has 30 per cent of the UK television audience and half of radio.

At the same time, Murdoch will be as irritated as he is unsurprised to discover that ITV's desire to consolidate into a single company is supported by the BBC, as is the ITV companies' view that there is no need to legislate against common ownership of Channels 3 and Channel 5.

His only comfort is that this is very unlikely to be permitted by competition authorities so long as ITV has anything like its current 57 per cent share of broadcast advertising revenues.

How will government react to all of this? Ministers, it is plain, have not yet made up their minds. With the Communications Bill now unlikely to be published before late April, there's time for plenty more kicking and scratching.

hargreavesian@hotmail.com

Ian Hargreaves is director of the Centre for Journalism Studies at Cardiff University