So much talk of diversity, but so little desire to stop Mr Murdoch's dominance

For all her talk of plurality and diversity, Tessa Jowell, the Secretary of State for Culture, yesterday moved Britain's media industry one step closer to homogeneity and monopolisation. She almost invited Rupert Murdoch to add to his already unhealthy hold on the newspaper and satellite television sectors a bridgehead in terrestrial television by relaxing the rule that prevents him from taking over Channel 5 (presently owned by RTL and Lord Hollick's United Business Media). The script from here is as predictable as an Australian soap's; shortly after the passage of Ms Jowell's legislation, Mr Murdoch will take over Channel 5 and mutate it into a terrestrial Sky One.

Fans of The Simpsons, two solid hours of which were available on Sky One yesterday evening, might think that no bad thing. But the consequences for the future of British television could be grim indeed. In the first place, we are likely to see a further lowering of standards, though not so much from what Mr Murdoch does to Channel 5, sad as that may be for a station that has gone a good way towards rehabilitating itself from the days when it relied on "the three Fs" ­ football, films and, well, Confessions of a Driving Instructor. The longer-term implications are much more worrying ­ a further erosion in competition.

For Mr Murdoch's market power will destroy what Ms Jowell calls the "ecology" of the media. With the demise of ITV Digital we have the unprecedented and dangerous prospect of Mr Murdoch's companies having a dominant position not only in parts of the newspaper market, but also in analogue satellite, digital satellite and digital terrestrial television and ­ through Channel 5 ­ a chunk of analogue terrestrial television.

That sort of market dominance creates great and irresistible temptations. It means that viewers would be left with less choice and expensive programming. It means that Mr Murdoch's companies might well be the only commercial bidders for both Premiership and Nationwide League football matches and other sporting events. It means that the films and series made by Mr Murdoch's studios could be available through even fewer outlets. What does Ms Jowell imagine would be the cost of pay-per-view Sky Sports or Sky Moviemax then? And what, we might ask the Government, would be the effect on our democracy to have so much media power in so few hands?

Of course, the Government claims, the new regulatory regime would be able to deal with this. Yet much of Mr Murdoch's output is already beyond the reach of the UK authorities, and even the toughest regulator is no substitute for real competition, which, despite some of his pioneering free-market rhetoric, is something Mr Murdoch has always done his best to crush. We have only to look at his cynical undercutting of ITN's bid for the ITV news contract or his predatory pricing tactics in the newspaper market to see that.

One, vain, hope is that a merger of Carlton and Granada could produce a powerful ITV champion. Yet they are so indebted and their credibility and brands so enfeebled after the fiasco of ITV Digital that their best future may lie in being bought by RTL or another large group. The BBC could, if set free, become a truly global player, but it seems to lack the will to do so.

So it is hard to welcome Ms Jowell's mini-bonfire of controls. She is creating an environment in which media power will be in even fewer hands. And when that happens, who will say "No" when Mr Murdoch seeks a further "relaxation of the rules"?