When we think of great speeches we often recall Martin Luther King’s “I have a dream”. But when Rowan Atkinson declares “I have a joke” you might also be moved to tears: boy did I shed tears of laughter over Atkinson’s father of the bride speech, one of his best-known sketches. After listing the manifold attributes of a charming, successful, virile young man named Martin, Atkinson pauses: “I therefore ask the question — why the hell did she marry Gerald?”

If the press hoped for similar chortles when the comic actor-cum-writer addressed them last week, flanked by lords from the upper house, they were disappointed. Atkinson was in earnest, denouncing ministers for attempting to outlaw the ridiculing of religion. You have to hand it to Charles Clarke; it takes a kind of genius to be demolished in an argument by Mr Bean.

They were treated to a forensic dissection of a bill that could see anyone prosecuted for daring to insult any religion that even Atkinson’s old school mate, Tony Blair, would struggle to counter. Hitherto the nearest Atkinson, 50, has come to politics was when one of his Aston Martins conked out; one of the few men who owned more cars than Atkinson was passing and gave him a lift: Alan Clark. Atkinson’s best man, Stephen Fry, tells me his friend must feel very strongly to speak out.

Now, Atkinson discloses, if the bill passes he is minded to stage a sketch to provoke the authorities into prosecuting him. Well, if they banged up Bean not only would it make the law but the entire Labour government an ass. Atkinson finds ministerial support for the bill — which is subject to a vote in the Lords on Tuesday — so inexplicable he wonders if it is “payback time”. “Are there any records of religious people giving vast sums of money over the years? ” Be careful, Rowan: you don’t want a knock in the night.

So why does he feel so passionately? “I suppose I am very aware of the freedom of expression I have enjoyed, particularly in clerical matters.” A reference, this, to his propensity to play vicars; by delicious irony, just as the bill could receive its royal assent, Atkinson will appear in a dog collar with Kristin Scott Thomas and Dame Maggie Smith in a film provisionally titled Keeping Mum: “ What is interesting about the vicar is he discovers the way to spread the word is to tell jokes.”

It is not a rhetorical device likely to be employed by Abu Hamza, the hook-handed Muslim cleric, but it poses a serious question: why are Islamic fundamentalists fearful not merely of criticism, but fearful of laughter? “It is an inability to take insults, mirrored by an inability to express their own view,” Atkinson says after careful thought with that familiar, schoolmasterly annunciation. “Some Muslim communities are inward looking and think the rest of the world can hang. It is based on a fear of the outside world.”

But before Islamic sorts dismiss Atkinson as “anti-Muslim”, he says he feels he should spend a stint with a Muslim community to learn of its fears. And he points out: “There are certain evangelical Christians who have been hankering for centuries for something a little more draconian, and this bill is it.”

He is on more controversial ground when he says a new religious hatred law could be used to prosecute too many people, just like, he suggests, the race discrimination law. “We thought that was meant to just outlaw nasty people who wanted to, in their vernacular, ‘stab a Paki’, but it has been used much more widely, such as after a dispute about a chair in a library when a white man said ‘go back to your own country’. It was a witless remark because the other man was standing in the country in which he was born, but I thought the law was meant to apply to cases more threatening than that.”

Hmm: this is dangerous ground. No wonder he rings later to “clarify”: he merely wanted to show that laws can be used in unexpected ways. His objection to the religious hatred bill is not that it makes it illegal to insult the person but illegal to insult the faith.

Lord Carey, the former Archbishop of Canterbury (in the trench with Blackadder in the Lords last week) said Muslim leaders asked him: “Surely you must have been insulted by The Life of Brian?” And he said: “No, I found it funny.”

Atkinson, who lives in some splendour in an Oxfordshire manor house with his wife and two nippers, insists he is not motivated by loathing of Labour. “I don’t have a deep-rooted view of the government but my view of it will be tarnished if we don’t get some movement on this.”

He points out that opponents of the bill “don’t have a political drum to bang — people like Stephen (Fry) have otherwise supported the government”. He suspects the bill has been driven from “the very bottom and the very top” — ie, Blair, who was two years above Atkinson at the Chorister school, Durham. Rather damningly, Atkinson says: “I can only vaguely remember the face.”

But to cut to the chase, do we really have a right to call someone, say, a Muslim moron? “To call someone that would be unpleasant, but would it be impossible to deal with? It is just the same as calling someone a red-headed moron or a short moron.”