TensionS were high, as were expectations, when it was announced that Professor Richard Dawkins would be addressing an audience in Stornoway in 2012.

Tabloid headline writers began polishing up the verbs that always get an outing when Hebridean hard-liners speak their minds.

To the disappointment of some, the island's ministers behaved impeccably. Yet what nobody - except perhaps Dawkins - had predicted was that this sell-out event, during which the evolutionary biologist spoke for two hours on the subject of The God Delusion, would result in a standing ovation. This, it transpired, was less for his debunking of God than for his trenchant views on Islam as an "evil" religion. Having demolished this faith wholesale, Dawkins added the mollifying rider that "the vast majority of Muslims" are not themselves evil, only their religion.

Getting Stornoway to eat out of his hand is but one of the secular miracles Dawkins has performed in his long, distinguished and sometimes eccentric career. So, when the central character of Dan Rhodes's new novel is revealed as none other than the great professor himself, the reader knows they'd better hold on tight.

Rhodes, who pours scorn on his cornflakes of a morning and takes two lumps of sarcasm with every cuppa, is one of the most engagingly childish yet savvy satirists around. In this, the first of his novels he has published himself, he is both scathing and tender, giving the reader a farce that spins like a carousel, yet still manages to tell a good story and settle a few theological scores.

Little England is his setting. One day late in the year, Richard Dawkins and his "male secretary" Smee are en route for a public speaking engagement in Upper Bottom, where the professor is to address members of the Women's Institute. These worthies are expecting an enjoyable speech; he, however, intends to convert them from their delusions of a deity, and turn the entire church hall from the path of religious ignorance towards the atheistic light. A leading member of the British Humanist Society, and a passionate atheist, "the thrice-married" Dawkins as Rhodes repeatedly describes him, is on a mission to stamp out belief in mumbo-jumbo and instil rational, scientific thought in its place. As his mantra goes, "everything has a scientific explanation".

The professor's problems begin when snow alters his plans a few days before his talk. Stranded in the village of Market Horton, some miles from their destination, he and Smee find themselves in a B&B run by a semi-retired vicar and his wife. Rhodes extracts maximum mileage from this mismatch, as you would expect, broad humour that begins with the vicar's wife laying out a display of gnomes in the professor's room. Her attempt to ingratiate herself with this reference to his famous field of research is only the first of many malapropisms.

Rhodes's portrait of the fictional Dawkins is on the far side of caricature, so rich in ridicule it makes a lampoon look limp. "My life would be so much easier if everybody was as clever as me," the professor sighs, meanwhile planning his series of children's books. The first will be called Your Parents Are Idiots, "aimed at children unfortunate enough to have been born into religious households".

Dawkins as depicted by Rhodes has few outside activities beyond his work, other than watching Deal Or No Deal. He does, however, own a stable of hobby horses. Among these are his views on cannibalism and infanticide ("I would have no moral objection to a little bit - just a tiny little bit - of infanticide") and on child abuse as practised by the church. "There has never been an atheist child molester," he says, as a proud member of Humanists Against Molestation, and he is happy at any point of a conversation to elaborate on "the movement's official stance on the moral differences between violent buggery and mild touching".

As Smee's job grows increasingly to resemble a delicate diplomatic posting, smoothing ruffled feathers as the professor erupts at anyone who dares believe in God, When The Professor Got Stuck In The Snow starts to resemble a Miss Read novel. Filled with appealing characters and their backstories, it offers a budding romance for miserable Smee, and even the chance of redemption for the obnoxious professor.

At times Rhodes bangs his drum too often and too loud, but he is such a vivid and elegant writer that is quickly forgiven, though perhaps not if your name is Richard Dawkins. Yet behind the mockery lie some deeper reflections: about how people should treat each other, the meaning of respect, and the ingrained need that everyone feels to make sense of our existence.

Rolling up his sleeves, Rhodes goes hammer and tongs at the likes of Dawkins and his mouth-frothing kin. No less a figure than Nobel laureate Peter Higgs, a physicist, has called Dawkins a fundamentalist, and Rhodes takes the same tack, neatly using the real-life Dawkins's intractable views to skewer his fictional persona. By its end, it is clear that the conceit of many scientists in believing science has all the answers is as much a target of this book as its most high-profile proselytiser. If it weren't too pompous a description for Rhodes's comical jeu d'esprit, this could be called a novel about the search for truth and tolerance.

In earlier books, Rhodes has shown he likes order, calm and kindness. A strong vein of domesticity and sentiment runs through his work, not to mention a predilection for pubs and their cosy hospitality, especially on cold winter nights. When The Professor Got Stuck In The Snow is perfect for such an occasion. Thoughtful, hard-hitting but above all amusing, it joins that groaning and enjoyable shelf of literature in which snow brings together an ill-assorted group. By the time it melts, everything and everyone has changed.