ISRAEL blackmailed President Clinton with phone-tapped tapes of his steamy sex talks with Monica Lewinsky, a blockbuster new book charges.

The price Clinton paid for the silence of the Mossad spy agency was calling off an FBI hunt for a top-level Israeli mole allegedly installed at the White House.

The allegation appears in “Gideon’s Spies – The Secret History of the Mossad,” written by respected author Gordon Thomas and due out next week.

Asked for comment, White House spokesman P.J. Crowley replied, “The only thing I can possibly say is we’ll skip the book and wait for the movie.”

Israel has denied conducting spying operations in the United States.

But hints about the Mossad connection to Sexgate surfaced in evidence given to independent counsel Kenneth Starr last year.

Lewinsky testified under oath that after a session of heavy petting and oral sex in the White House, Clinton told her that a foreign embassy was tapping the two phone lines in her D.C. apartment.

She said Clinton advised her that if she was questioned about their phone-sex sessions she should claim that they knew their calls were being bugged – and were joking to make the phone-tappers look silly.

Starr did not pursue the matter, as far as the public record shows, and Lewinsky apparently accepted Clinton’s story without asking for details.

But author Thomas says Danny Yatom, Mossad inspector general, succeeded in tapping Lewinsky’s phone and amassed some 30 hours of sexually explicit conversations between the president and Lewinsky.

Thomas says Tel Aviv used the tapes to stop the probe of an operative code-named “MEGA,” who was, and could still be, deep within the White House.

“So far as anyone knows, the Israeli agent MEGA – a much more important spy than the imprisoned CIA traitor Jonathan Pollard, and probably his controller – is still in place at the White House,” Thomas said last night from London.

“There was a flurry of high-profile counterintelligence activity which lasted as long as the bioleverage” – that is, blackmail – “took to work.”

His book – which coincidentally is published by St. Martin’s Press, like Andrew Morton’s “Monica’s Story” – claims the decision to use the Lewinsky tapes reaches high levels in Israel.

Israel’s Committee for Central Intelligence, meeting in emergency session, decided to play dirty by exploiting Monica’s steamy chats as a way of protecting their White House “asset,” Thomas said.

“FBI counterintelligence, which had also been taping Monica’s calls, got the message and decided to go back off,” the Welsh-born author claims.

Verifying Thomas’ account is difficult because spy agencies almost never comment on their activities or anything anyone writes about them.

It’s been reported that the Justice Department and FBI launched an investigation last year for a suspected mole, code-named “MEGA,” based on undisclosed evidence that an Israeli spy had penetrated the White House.

Israel heatedly denied a mole existed, saying it had ended such spying with the arrest of Pollard more than a decade ago.

Officials in Jerusalem said MEGA was the code name for a U.S.-Israeli intelligence sharing arrangement to fight terrorism.

In any event, nothing has been heard of the U.S. pursuit of MEGA in a year.

The alleged Mossad connection adds a new dimension to Sexgate – and could even support Hillary Clinton’s charge that a “vast, right-wing conspiracy” was out to destroy her husband’s presidency.

Asked about that, Thomas replied: “That’s not for me to say.

“I can only report the facts as I found them. What you make of the facts is up to you. What Monica makes of them is up to her.”