In todays press (28 Dec), there is a report based on a hansard answer suggesting that the MOD has 690 press officers. Cue massive complaints across the board, and perceptions that the MOD somehow has an entire batallion of press officers ready to do battle with the true enemy of fleet street. (http://newsnetscotland.com/index.php/scottish-politics/3960-mod-criticised-for-spending-on-media-personnel-in-wake-of-defence-cuts)
The reality is somewhat more prosaic - all units at any reasonable size have a press officer. Its usually a job given to whichever junior officer or SNCO isn't fast enough to get out of the way. The role is simple, try to turn the general activities of the unit into something which over time can be used across social media, press, networking sites and so on in order to show what the unit is doing, and how this adds value to the MOD, and justifies taxpayers spending money on it.
Larger units have their own more full time press officer (by full time I mean maybe a largeish chunk of the day is spent on these jobs), and at a more strategic level - e.g. maybe Division, Command or MOD HQ you'll see full time press officers. There are, of course, exceptions to this rule, but the reality is that in the UK, very few staff do full time press work. There are embedded media teams in operational theatres, and a variety of full time press handlers in the MOD. Similarly, there are reservist media teams, manned by media professionals who are also members of the armed forces, and which handle media issues in their spare time.
The problem MOD has it that in media coverage, its actions will inevitably breach 'Humphreys first rule of war', namely that 'you are damned whatever you do as experts will show you how you should be doing it instead'. If the MOD chose not to have people doing media work, then no doubt there would be complaints across the board, people saying that they didnt understand how the MOD worked, or what it did with its people. The memories of the self righteous indignation of the press from 1982 are a classic reminder that the media will quickly turn on those who seek to deny it news.
However, by maintaining press officers, the department leaves itself open to ridicule and scorn by those who believe it is wasting money on this stuff, and there is no need to do so (usually the same people who'd complain when not allowed into an operational theatre).
The reality is a happy medium needs to be struck - the public have a right to know what the MOD does, and how its using taxpayers money. To this mandarins mind, engaging the services of under 700 people, for the most part on a part time basis, out of over 270,000 in defence isn't a bad way to keep the public involved. For this investment the MOD can try to show what it gets up to, can try to source new recruits and also help maintain the information offensive, which is as crucial an operational battle as armour or warships in the 21st century.
The final thought should be that if the MOD didnt employ press officers, then the papers would probably lead with stories of scandal about how dreadful it was that the MOD wouldnt tell anyone what was going on, and surely the public have a right to know...