21 JULY 2007, Page 38

Dear Diary Bryan Forbes says that journals are rev

Dear Diary Bryan Forbes says that journals are revealing — about their writers Iv hat compels people to keep a journal? Is it because conceit persuades them that posterity must not be deprived? My night thoughts pondered this during the week that Alastair Campbell's opus was unwrapped. As far as I can make out he saw himself as the all-seeing camera eye at Blair's ersatz Versailles court. Unfortunately an apprenticeship writing for the fetid pages of Forum magazine does not make one a Duc de Saint Simon. Or put it another way: if the Duc was a Chippendale bureau, Campbell is more a flatpacked kitchen table from Ikea.

I suspect that, subconsciously or otherwise, those who diligently make the effort to record the day's events before retiring embroider the facts: sometimes for honourable reasons, to spare pain to the living, sometimes less than honourably if they are intent on settling old scores and determined, whatever the true facts, to depict their own behaviour in a favourable light.

Campbell, the erstwhile spinmeister, has let it be known that he was forced to let his masterpiece be got at and toned down lest it betrayed the holy writ of New Labour.

In most cases journals reveal more about the authors than their victims, for when venom stains the pages the reader perceives he is being manipulated by somebody who is patently unfulfilled; when all is praise it becomes transparently obvious that the writer is touting for future favours from those he is sweetening. Today more and more politicians and their groupies feel the compulsion to cash in immediately after they are deprived of the perks of power; a week is not only a long time in politics, it is also a long time on Waterstone's shelves for most of them. Who now bothers to search out a copy of Barbara Castle's memoirs or, more recently, the indiscreet meanderings of David Blunkett?

When I was much younger and struggling to become a novelist, I felt it important to study the trials and tribulations of famous writers such as Maugham, Arnold Bennett and the Brothers Goncourt. I convinced myself that if I followed their example, my own success was assured, but when I tried to emulate them the method did not work for me, mainly because my life at that time contained nothing of interest to others and my journals were mostly concerned with the debris of unrequited loves.

Despite this I have always remained fascinated by the way writers live and work, even when, as in the case of Proust, they recycled their cork-lined life as fiction. The great American critic Edmund Wilson laced his erudite reminiscences with the frankest of sexual confessions. Evelyn Waugh, who kept a diary from age seven, cast his baleful eye over the social history of his times, while the waspish Cecil Beaton published six volumes of memories in his lifetime but doctored the entries, and the unexpurgated texts were only issued after his death.

While alive he beautified and retouched his life just as he retouched his photographic portraits, and the posthumous volumes revealed he was not only high camp but vicious. I recommend him and Waugh to students of venal human behaviour, but if you wish to enter the world of a gentle, brilliant but doomed writer and share her take on a life foreshortened by illness, find a copy of Katherine Mansfield's journals.

I fear that future generations will be starved of like pleasures for it is difficult to believe that internet bloggers will bequeath anything of lasting value to posterity and their blather will disappear into cyberspace. Likewise emails and the rising cost of postage stamps have signalled the demise of letterwriting — that most civilised means of communication between friends.

The further we allow ourselves to be distanced from the written word, the more impoverished we must become. Publishers must share the blame for this because they have gradually debased their own currency; books are now treated as commodities, stacked high and sold cheap as loss-leaders in supermarkets while independent booksellers — those who have long struggled to keep the flame of literature burning by stocking a wider range than transient bestsellers — suffer and go under.

Political diaries and journals, if fearless and written with panache and wit (bring back Alan Clark) can be an invaluable tool for future historians, but if cynically used as a personal propaganda tool, as I suspect in Campbell's case, they reveal nothing but opportunist chicanery.

Bryan Forbes 's latest novel The Choice is published by Matador at £8.99.