Police were called to Borders bookshop in Oxford amid scenes of uproar at a talk given by the controversial philosopher Andrew Malcolm.

Members of the audience were escorted from the shop in Magdalen Street as the author tried to continue.

Borders staff began to remove chairs and tables and Mr Malcolm and his supporters staged an impromptu sit-in.

He was eventually led outside by police officers. He later angrily accused Borders of depriving him of freedom of speech.

But Borders said that the shop had already cancelled the talk and that Mr Malcolm had chosen to ignore the decision.

Mr Malcolm has been involved in a six-year feud with Oxford University after the Oxford University Press declined to publish a book he had written.

He was at Borders to sign copies of his philosophical work Making Names and a second book about his court battle with OUP, which left him with a £12,500 legal bill.

Mr Malcolm said: "This must have been the oddest invited book-signing in history; no window display, no poster, just an author quietly addressing his peaceable audience, while a team of security men solemnly requisitioned their table and chairs. It was not so much Nazi Germany as Monty Python. "Now we know what free speech means in Oxford. In a way it's flattering. I never realised that what I have to say is so dangerous."

Penny Fox, a lecturer who was in the 12-strong audience, said: "It was an extraordinary scene with an author and a handful of his middle-aged audience being escorted from Borders by police because the manager considered a book inappropriate.

"The atmosphere was so intimidating and slightly frightening. I found this situation out of control. Fortunately, when the police arrived they handled it very well."

Another member of the audience, Elizabeth Wilkinson, who travelled to the event from Maidstone, in Kent, said the experience had put her off visiting Oxford again.

She said: "On my arrival I was told the talk was cancelled. The audience was encircled by security men who proceeded to remove the chairs and table.

"We refused to move and were eventually escorted from the shop like criminals by a team of uniformed police."

Philip Downer, UK managing director of Borders Books & Music, said slow sales of Mr Malcolm's books suggested the talk would attract little interest and he was told on September 27 that it had been cancelled.

He said: "Mr Malcolm chose to arrive in any case and stage an impromptu event in the store, and the manager felt it prudent to call police to avoid a disturbance.

"We're always disappointed when we have to cancel an event, and it was unfortunate that some members of the public were unaware of the change of programme, although cancellation notices were prominently displayed in the store. Mr Malcolm's books remain in stock."

Oxford University and the OUP said that they were not involved in the decision to cancel Mr Malcolm's talk. Caroline Mainprize, of the OUP, said: "We were not even aware that it was taking place."

A spokesman for Oxford police said: "Police were called to Borders bookshop after a disturbance. Officers attended and the group left the shop. No arrests were made."