The announcement last week that Theresa May is setting up something called the 'National Security Communications Unit' charged with combatting disinformation by state actors and others' should be welcomed by all those concerned about the apparent growth and influence of fake news.

But not by me.

Apart from this looking like the knee-jerk (and usually un-thought through) response by politicians to the cry "something must be done" (think Dangerous Dogs Act), I am not sure that there's a real problem here in the first place, at least not in the context of UK domestic news.

Fake news has three distinct meanings, and only one of them is legitimate.

First there is the real deal - pimply youths (or older versions) sitting bedrooms in Macedonia, and elsewhere, thinking up entirely fictitious stories as per 'Pope Supports Trump' - done either for monetary gain (via the clicks) or political propaganda.

Second, there is the use of the term as a general insult, principally used by the President of the USA, to undermine any report, or media outlet, that is not to his liking.

And third there is the variant that we are most familiar with here - what could be termed "extreme spin" - for some reason buses and the figure £350 million springs to mind. But the difference between this and 'real' fake news is that this claim, like most spin and propaganda, is based on a scintilla of fact which is deliberately spun in order to deceive.

In this incarnation it is clear that this variant of fake's news is something that has always been with us in one form or another, perhaps the first post-war example was Churchill's scaremongering claim that a post-war Labour Government would be akin to the Gestapo.

But this is not to suggest that we can be entirely sanguine about category one - the real deal. There seems little doubt that Russia, and probably many other international state actors, have been disseminating unambiguous fake news – a classic example being the claim that the White Helmets in Syria who have been rescuing people from bombed and shelled bookings, are in fact a front for one of the Jihadist militias.

Nonetheless, in the domestic context, there is little evidence of a sustained attempt to introduce demonstrably invented stories into the political arena (as opposed to other parts of the news agenda) and if there has been then it's fair to say that their impact has been approximately zero.

But there are other aspects of the National Security Communications Unit that are of concern. First, how is it going to establish what is false news, as opposed to mistaken reportage or propaganda – it's notoriously difficult; and given that such an operation only makes sense if can act speedily then its task, even if it can be defined, becomes mind-boggingly difficult.

Second, we know from the experiences of Facebook and Google that the algorithm has to be invented that can actually detect fake news, let alone decide what is one person's fake news and what is another person's matter of opinion. The only way that the online giants have been able to deal with the problem is by employing vast armies of human monitors and fact-checkers. Facebook is reportedly employing 20,000 such bods – is the new Unit thinking of employing a similar number and at what cost?

Although conspiracy theories usually turn out to be more cock-up than conspiracy there is something chillingly Orwellian about the name of the Unit 'the National Security Communications Unit' that leaves me feeling a tad nervous. Will they publish their criteria for checking and blocking what they call fake news – and how are they going to find it in the first place – targeting?

If it was clear that fake news is a major problem for the UK then such an initiative should be welcomed, albeit cautiously. But it is not and hence the question has to be asked what's going on?

Ivor Gaber is Professor of Political Journalism at the University of Sussex and is a former political correspondent based at Westminster.