The German-speaking world of Kafka scholars hit out yesterday over a British academic's claims that the writer had a penchant for hard porn.

James Hawes, a Kafka expert and novelist, claims in his book Excavating Kafka, published in Britain yesterday, that the writer was a subscriber to upmarket pornography. Furious German academics reacted by accusing Hawes of prudishness, sensationalism and even antisemitism.

"Hawes has given us a look through the keyhole of a Kafka with his trousers down ... but to call the illustrated magazines he subscribed to as hardcore porn, is like comparing a poem by Heinrich Heine with an advertising slogan for McDonald's," wrote Anjana Shrivastava, a Kafka researcher on Spiegel Online, calling Hawes a "prude". She said he had made himself a "preacher of hate" in the world of Kafka scholars.

Critics also dismissed Hawes' claim that Kafka kept his pornography under lock and key in a safe on his bookshelf, saying it contained instead a savings book he did not want his family to know about.

The legendary German Kafka critic Klaus Wagenbach, who has published numerous coffee-table books on the Prague-born writer and made mention of the pornographic images in a book he published in 1958, told the Frankfurter Allgemeine: "This is some idiot ... who knows nothing about Kafka, but writes about him as if he did."

Rainer Stach, a Kafka biographer, said the furore surrounding the book was an "unbelievable marketing ploy". No one had ever said Kafka was pure and chaste, but the "pornographic" pictures were "playful representations, some styled like caricatures".

At the focus of Hawes' investigation are pictures he stumbled across in the British Library in London and the Bodleian in Oxford of the pornography to which Kafka subscribed while in his twenties. They include images of a hedgehog-style creature performing fellatio, golem-like male creatures grasping women's breasts with their claw-like hands and a picture of a baby emerging from a sliced-open leg.

But Hawes, an Oxford graduate who teaches creative writing at Oxford Brookes University hit back at his critics, claiming that none of them had read his book and accusing them of operating a "conspiracy of censorship". He said he had made no claims to have discovered Kafka's penchant for pornography and brothel visits, but had explored why Kafka scholars had chosen to virtually ignore the topic.

"We're talking about a writer whose psyche the experts have been so keen to decipher. They have pored over every memorandum he ever wrote, every insurance report he ever compiled, looking for clues. Yet they have chosen not to show this undoubtedly very dark stuff," he told the Guardian.

"I don't remotely claim it's a discovery of mine, but I was genuinely shocked when I first saw it, because I had never seen it in any academic biography of Kafka. The experts' conspiracy of censorship is entertainingly curious."

The angry response to Hawes' book has extended to accusations of antisemitism. Shrivastava said Hawes was more interested in "speculating about whether or not Kafka masturbated" than exploring theories that the Jewish writer, who died before the Holocaust, had foreseen it.

Hawes said the antisemitic claims were "outrageous and extraordinary ... The Holocaust happened after his death, so it's ridiculous to talk of his works in that light," he said.

But one German critic at least, welcomed Hawes' book. "We are devastated and furious, but at the same time happy," wrote Ulrich Weinzierl in Die Welt. "Finally the literary stylite has fallen from his pedestal ... and is as much a sinner as you or I."