The news that the BBC is planning to share its studios and other facilities with ITV regional news indicates that the fortresses of British public service broadcasting are coming tumbling down.

In the past the various commercial companies such as ITV, Channel 4 and Five competed rigorously against the BBC for stories, audiences and impact. Drawbridges were raised against rivals, while news teams clashed over interviews and scoops. Now the ITN regional journalists making the news for Michael Grade will increasingly rely on BBC material and buildings.

At a practical level, anything that saves some plurality in regional news has got to be a good thing. ITV argues that it is facing oblivion in a multi-channel age if it can’t free itself from some of its public service obligations. But is this just a stop-gap measure to keep ITV regional news going for another few years?

I think it may well be just a way of putting off the inevitable. But regardless of the fate of ITV regional news, it does pose a fascinating question for the BBC. With talk of a partnership with Channel 4 and BBC Worldwide it appears that the BBC is becoming the national broadcast hub. It is the Railtrack of UK media.

The BBC has adopted this strategy of co-operation and partnership for quite expedient reasons. A year or so ago it recognised that it faced the prospect of slices of its income being hived off to support rival broadcasters. Far better, it was argued, to create relationships where the BBC offers support but remains the dominant partner and in control of its resources.

All this may sound cynical. I am sure BSkyB will feel very cynical about all these crippled public service broadcasters propping each other up with taxpayer’s money. As Murdoch’s men have pointed out, the licence fee is, in effect, being used to bail out commercial rivals who have run into trouble. What is it that ITV produces that gives it more public service value than say, Sky News and Sky Arts?

Well, one answer might be regional news, which is why that is the service that will get the helping hand from the BBC. But beyond this is a much bigger picture. Does this mean that the former fortress of the BBC is going to become an open house for other public service media organisations? Is the BBC the PSP in disguise?