"Dear Sir. . . She Who Dared ISBN No 085052 696-8. . . We must ask you immediately to return your copy of this book to us. . . We will send you a replacement copy as soon as possible. "

As a book promotion, this letter to literary editors earlier this month, from the respected military publisher Leo Cooper, obviously had hidden depths; an opacity in keeping with its subject matter: the undercover war in Northern Ireland. That an injunction had been obtained by the ministry of defence to suppress the book, two months after publication and long after the ministry itself had "cleared" (ie, censored) the work, was not mentioned.

Nor, for that matter, has HarperCollins explained to retailers why the paperback of my own book about the Troubles - The Irish War - remains unpublished following an advisory letter from MoD saying "Don't !" This deterrent was one that succeeded without even the formality of a court order to back it up.

Is this a new trend in book marketing? A negative buoyancy test to affirm the true importance of a book about Britain's last colonial war? Should publishers collude in the process? Or is the inconsistent behaviour of MoD - first allowing a book to be published, and then having a paroxysm of post-publication regret - the military equivalent of coitus interruptus , left, as so often with this technique, too late to avert disaster?

For there are, to my personal knowledge, at least three uncoordinated (and apparently competing) censorship teams setting out to hunt down wayward authors and publishers from their separate lairs within the same ministry. In view of the singular attention attached to She Who Dared, what is special about this book ?

It is one of three recent memoirs derived from the experience of the undercover, armed, plainclothes team commonly known as 14 Intelligence Company. The company comprises three detachments ("the Dets"). Their surveillance techniques include armed, illegal entry into private premises. The three authors, writing under pen-names - "Jackie George" (a woman soldier, now a freelance bodyguard), "James Rennie" (an infantry officer, now a stockbroker), and "Sarah Ford" (a woman sailor, now also a freelance bodyguard), cover the years 1983-91. All publish identically-worded health warnings at the front, a mantra apparently prescribed by Whitehall: "Owing to the sensitivity of the contents of this book, the manuscript was submitted to the ministry of defence prior to publication. At their request some changes were made to the text - including altering the names of individuals and places - in order to protect the work of the unit in their fight against terrorism."

One would think that this set all three authors on the same footing. But Jackie George's book is the one that has been blasted with an injunction. (None the less, it continues to sell well, particularly in Hereford, home of the Special Air Service.) Among many marvels attached to this decision is the fact that although recently published, it covers the most remote time-frame of the collection, 1983-88.

The censorship of Jackie George's story displayed Whitehall's characteristic incompetence even before the injunction. For example, the names and places changed include that of an SAS soldier, Al Slater, shot dead by the IRA in Fermanagh in December 1984. Why now conceal Slater's identity when it has been in the public domain - including two of my own books - for most of the preceding six years? Why cut out any reference to the deaths of two IRA men, Tony MacBride and Keiran Fleming, in the same contact? It would seem that the censor does not know what has been published already and what has not.

Yet from such ignorance is asserted the right to suppress information which, since it does not damage security, the public has a right to know.

Jackie George's book shares common features with the other two, including an account of the brutalising nature of the selection process. "Resistance-to- interrogation" licenses the selectors to deprive their masked, female subjects of the right to go to the loo. If they have the "bottle" to wet themselves before the prurient gaze of their male interrogators, that wins brownie points.

Both of the women authors, as it happens, came from dysfunctional working-class homes where violence had already marked them. Service with Britain's secret army in the war against terrorism left them psychologically more damaged than before. No help was offered to stabilise them after the trauma of blood, booze and brutality across the water.

Where Jackie George breaks the mould is in her attitude to the Royal Ulster Constabulary. (Ford, by contrast, decorated her bleak quarters with a King Billy tea-towel.) George describes the successful surveillance of a loyalist arms transfer, an operation which greatly displeased the RUC special branch. Her partner, Joe, "thought we had all done a good job in locating these terrorists, regardless of their political persuasion. However, it seemed that the RUC was only concerned with apprehending republican terrorists. We were told in no uncertain terms that we were never to work that area again. Under no circumstances were any records to be kept."

Or: "The police, who had jurisdiction over the army, seemed to believe that they could do whatever they wanted and get away with it. The sad truth was that they probably could. . . They could even arrange for you to die if it suited their purpose." Or, again: "The bitterness I felt towards the special branch of the RUC will remain with me always. Those police officers played with our lives with total indifference and many of them were no better than the terrorists they were supposed to be fighting."

To publish such sentiments at a time when the Patten report was about to recommend drastic reform - a virtual demolition - of the RUC was to invite some sort of reaction. Did anyone invite Jackie George to give evidence to Patten? It seems unlikely.

The chosen option was to shoot the messenger; or in this case at least to suppress the message. In the Irish war, truth is not just the first casualty. It promises to be the last and most permanent one also.

• Tony Geraghty's The Irish War is published by Johns Hopkins University Press. He was charged under the official secrets act, which led to widespread public protests; the charges were later dropped, but secrets charges are still pending against a decorated bomb-disposal officer, Colonel Nigel Wylde