U.K. Prime Minister David Cameron gave his first public reaction to a biography that contained lurid allegations about his past, saying everybody could understand why the book had been written.

The book, "Call Me Dave," by former Conservative Party Deputy Chairman and Treasurer Michael Ashcroft and journalist Isabel Oakeshott, made headlines over the past week as it was serialized in the Daily Mail newspaper. The Mail on Sunday newspaper reported that Ashcroft fell out with Cameron when he wasn't given a Cabinet post after the 2010 election in return for millions of pounds of donations to the Tories.

"Everyone can see why the book was written and I think everyone can see straight through it," Cameron told reporters Sunday as he flew to New York for a visit to the United Nations.

Asked about one allegation concerning a bizarre initiation ceremony involving a pig while a student at Oxford University, Cameron said that "as for the specific issue you raised, a very specific denial was made a week ago" by his spokeswoman. "I've nothing to add to that."

Ashcroft was cited by the Mail on Sunday as saying he had a "beef" with Cameron and the junior job he was offered at the Foreign Office was not a fair return for everything he had done for the party.

"After putting my neck on the line for nearly 10 years — both as party treasurer under William Hague and as deputy chairman — and after plowing some £8 million ($12 million) into the party, I regarded this as a declinable offer," the newspaper quoted Ashcroft as saying. "It would have been better had Cameron offered me nothing at all."

Ashcroft denied that the book's purpose was to "settle scores," the Mail on Sunday said.