The National Union of Teachers has a long and often distinguished history of battles under its belt: the testing boycott, the 1980s strikes, tussles with the militants. And now: the wrangle over the authorised biography of the last quarter-century.

Someone in Hamilton House had the bright idea of commissioning an update of the union’s official history to mark its 125th birthday, and a budget of Pounds 175,000 was earmarked. A roster of distinguished education journalists was canvassed: rumour has it that Roy Hattersley was one name suggested. The honour eventually went to Stephen Bates, of the Guardian, who was given a breakneck four months to turn in his typescript.

Despite moving to Brussels in the middle of research, Mr Bates duly completed his interviews in time and got his 150-odd pages to NUT supremo Doug McAvoy by the end of January, as promised, for publication during the Easter conference. Six months on, the manuscript of Put To The Test appears to have been read only by a very select handful of the NUT high command and a few friends of Mr Bates, while the aggrieved author has no idea what is actually happening, since meetings arranged with the union’s general secretary have been cancelled at short notice no fewer than nine times. Routine behaviour, according to one former insider.

“You’d think it was terrifically hostile to the NUT, but it isn’t,” says Mr Bates. “It’s a warts and all portrayal of the NUT, and it’s critical from the point of view of someone who is sympathetic to teacher unions.” The author, the former Guardian education editor, now writes on the European Union for the paper.

Before agreeing to the commission, Mr Bates says he made it “abundantly and repeatedly clear” that it would be a critical book. The book suggests that the union took the wrong path on joining the TUC in 1970 (ironically on a conference vote and against the wishes of the general membership) and - as some of the senior figures interviewed by Mr Bates agreed - made the mistake of going on to concentrate on pay and conditions rather than professional service issues, thus losing sympathy during the 1980s strikes. Provocatively, the opening words are: “It has been a very great fall.”

Early reactions seemed favourable, with a letter from Doug McAvoy enthusing about the manuscript as being “immensely readable and perceptive”. Then, silence. Mr Bates wrote in March asking after progress. Silence. He wrote again in May, at which point, he says, “Doug got a bit stroppy” and wrote back to say he did not think the NUT national executive would publish the book in its present form.

“This struck me as a bit strange, since I don’t think he’s shown the book to them,” said Mr Bates, who believes a very few officials have seen the manuscript, although these do not appear to include even Steve Sinnott, McAvoy’s deputy.

Meetings were arranged and cancelled, but all the author heard were odd comments from one official close to Mr McAvoy, who had been instrumental in the commissioning of the history. She, has, apparently, been advising prospective readers to start on page two - thus skipping the critical introductory paragraphs.

“I think Doug is nervous because on the first page of the book I say that the union has lost membership and has lost influence. I think that is self-evidently true: the union has lost membership and influence compared to 1970. One thing that was said to me unofficially was that might be giving a hostage to fortune to the National Association of Schoolmasters Union of Women Teachers, but I don’t know how true that is.”

Mr Bates points out that in the five months the manuscript has been in purdah in Hamilton House, he has not officially been told of anything demonstrably wrong with it. “Doug apparently wants to speak to me to get one or two points cleared up, but since then I’ve heard virtually nothing. I really don’t know what the problem is.”

It is not, he says, a hatchet job, although one or two people say outspoken things in it - including former Labour leader Neil Kinnock, who outlines his belief that the union lost public perception that teachers cared first and foremost for their pupils.

And one or two specific problems have found their way back through the NUT’s elaborate system of Chinese whispers. “I was accused of being nasty to Fred Jarvis. I said he would never use one word when 30 would do, and anyone who knows Fred would agree with what is a fairly mild criticism of him. And they didn’t like me quoting Max Morris saying he used to shit on the hard left from a great height at the party conference. They thought teachers would be offended by Max’s use of the word ‘shit’. It’s all so trivial I can’t believe it would hold the book up for month after month.”

Last week Mr Bates became so infuriated that he went public and a piece appeared in the Guardian, accompanied by this statement from Mr McAvoy: “No restrictions were placed on whom he chose to interview, although some may have felt that what they said was off the record. Having received the text, we began to talk to the author. The final stage was for discussion between the author and me prior to a decision on publication which would have been taken by the appropriate NUT committee before the end of the 125-year celebrations. That process is incomplete, and the author’s article in the Guardian is unhelpful and surprising.”

Mr Bates, who was paid for the book - Pounds 20,000 has gone to him and the publisher - is now considering trying to get it into print himself as copyright rests with him and no contract was signed with the NUT. “A bit silly, I suppose, but we trusted each other.”