That nice Alan Bennett takes the gloves off for Tory politicians, the Queen Mother - and Dennis Potter

Alan Bennett, in his original diaries, said that he wanted to be "liked and thought a nice man".

New extracts from the revised edition, however, will do nothing to endear him to many prominent figures in the worlds of politics, literature and entertainment.

He jokes at the expense of the Queen Mother, professes a desire to kick Michael Heseltine in the backside and describes the writer AN Wilson as "a silly prat".

A revised version of his successful diary, Writing Home, is to be published by Faber next month.

Most of the playwright's vitriol is reserved for Conservative politicians, with Baroness Thatcher and her "cronies" standing accused of having "uncivilised debate and denatured the nation".

Lord Tebbit is dismissed as a "sneer on legs, snarling and heaping contempt on any vaguely liberal view", while the Conservative MPs Tony Marlow and Edward Leigh are described as "fat and complacent and looking like two cheeks of the same arse".

The backside of Michael Heseltine is also a prime target for Bennett's boot. Or in the words of the playwright's father, he would like to "Joe Fitton" the Deputy Prime Minister.

Reminiscing, Bennett explains that his father had an aversion to using swear words but overcame the problem while an air-raid warden during the Second World War.

Joe Fitton, a fellow warden who was not normally known for bad language, lost his temper one night and said he would like to give the source of his anger "a right kick up the arse".

The expression "to Joe Fitton" was adopted by the Bennett family, and the playwright reveals his wish to do some "Joe Fittoning" to Mr Heseltine and Cedric Brown, the chairman of British Gas.

But Bennett does not restrict his line of fire to the Houses of Parliament. The man once described as "the kind of writer that mothers like" is quite prepared to snipe at his peers.

AN Wilson aroused Bennett's ire with an article in the London Evening Standard which compared the Yorkshire-born playwright to Liberace and Cliff Richard.

Bennett hits back at the perceived slur by recording his response in a new extract to the diaries: "`You silly prat' is what I feel, wondering how anyone who writes for such a rag as the Standard feels in a position to say anything about anybody."

Another writer, Lord Archer of Weston-super-Mare, is disparagingly compared to the comedian Bernard Manning.

Peter Cook, the late satirist, is affectionately mocked for his "deeply embarrassing" attempts to impersonate Elvis Presley and to quote passages of Shakespeare by heart.

Bennett also passes comment on his late friend's vanity. "Slim and elegant in those days, [Cook] was also quite vain, sensing instinctively as soon as he came into a room where the mirror was and casting pensive sidelong glances at it, while stroking his chin, as if checking on his own beauty," he recalls.

The health of the late Dennis Potter, says Bennett, was always a factor in his fame. "He visibly conformed to what the public thinks artists ought to be - poor or promiscuous, suffering or starved."

In pages peppered with deft, wry humour Bennett displays his sympathies for the poor, the homeless and the gay community.

His description of the Commons debate on lowering the age of consent for gay sex lauds the "civilised and courageous" words of Labour's Chris Smith in the face of bigoted opposition. Bennett observes: "The frail faltering flame of heterosexuality always in danger of being snuffed out by the hot homosexual wind."

Establishment figures are described with rather less reverence. Bennett quotes a joke about the Queen Mother in an old people's home and not being treated with the proper respect. The joke goes: "Queen Mother: Don't you know who I am? Nurse: No, dear, but if you go over and ask the lady at the desk she'll probably be able to tell you."

Writing Home topped the best-seller list and has sold more than 750,000 copies. The latest extracts are mainly taken from his 1993 to 1995 diaries.

Bennett, now a millionaire and still unable to do wrong in the eyes of critics, has shown an increasing reluctance to hold his tongue when others anger or irritate him.

In his 1996 diaries, he made a caustic attack on Classic FM listeners, who he dismisses as "Saga louts".

In an astonishing outburst he writes: "I loathe Classic FM more and more for its cosiness, its safety and its wholehearted endorsement of the post- Thatcher world, with medical insurance and Saga holidays rammed down your throat between every item."

When Bennett was described as "winsome" in an article in this newspaper he responded with typical wit by rejecting a subsequent interview request, saying "winsome, lose some".

And despite the potshots at others in the new extracts, Bennett is not short on self- deprecation.

He recalls how his pride got the better of him while he sat in a car in Yorkshire waiting to acknowledge a fan, walking towards him with a smile on her face.

To Bennett's surprise, the woman actually climbed into the seat beside him before exclaiming: "Only in Yorkshire ... bloody hell! I"m in the wrong car!" and rushed off to her waving husband.

Bennett writes: "The person who is really shown up by the story is, of course, me."