The man in the soundproof broadcast booth wearing headphones and an intense gaze is discussing Saudi Arabian history with radio listeners this evening, but it's not the kind the Saudi government would endorse.

Saad Faqih recites a list of "massacres and assassinations" that he alleges were carried out by the late Abdul Aziz Ibn Saud, modern Saudi Arabia's first king, in his rise to power nearly 100 years ago. Then Faqih pauses to take calls from listeners phoning in from his homeland to offer their own impassioned accounts of the royal family's alleged transgressions.

Just a few years ago, Faqih headed a small splinter group of Saudi exiles armed with a lone fax machine, a telephone and a dwindling list of contacts back home. These days, however, thanks to the Internet, satellite television and radio, cell phones and the largess of confidential benefactors, Faqih's message of dissent is beamed 3,000 miles to Saudi Arabia in a live three-hour broadcast every evening.

He describes that message as moderate and nonviolent, but at the same time he refuses to condemn al Qaeda and says that the United States brought the Sept. 11, 2001, attacks on itself through "arrogance."

The recent wave of violence against foreigners inside Saudi Arabia has enhanced his reputation as a well-informed observer and critic of the forces at work there. Academics, journalists and intelligence analysts beat a path to his home in north London.

Faqih's archenemy, the Saudi government, calls him a terrorist who is conspiring to overthrow the royal family and replace it with a strict Islamic government acceptable to Osama bin Laden. In a dossier shared with officials in Washington and London, the Saudis seek to link Faqih to a long list of suspected terrorists and accuse him of inciting violence.

Now the Saudis have produced a new allegation. They accuse Faqih of taking $1.2 million from an operative of Libyan leader Moammar Gaddafi to help arrange the assassination of Saudi Arabia's de facto leader, Crown Prince Abdullah. The Saudis are pressing British authorities to detain Faqih on suspicion of terrorism and shut down his broadcasts to the kingdom.

Faqih, 45, who was a surgeon in Riyadh before he fled Saudi Arabia a decade ago, denies all the allegations. Increasingly, he inhabits a twilight world where the line between dissident and terrorist sympathizer is blurred beyond recognition.

Since the Sept. 11 attacks on New York and the Pentagon , he has become more influential but also more of a target, as he himself acknowledges.

Faqih asserts that one member of the royal family hired two local thugs who attempted to kidnap him from his doorstep a year ago, in what Saudi officials insist was an unauthorized operation.

"I can assure you that the Saudi regime is using every means possible to attack me," he says. "They are bombarding the British authorities with false stories. And there are elements in the American administration who are conspiring with the Saudis to incriminate me."

An Unlikely Rise

The nerve center of Islah ("Reform") Radio is a small room in the back of an anonymous duplex, crammed with five computers, a few telephones, two sound mixers and an isolation booth constructed from plywood, plexiglass and duct tape. Faqih, who arrives just before 7:30 p.m., is dressed in a full-length, crisp white thobe, or shirtdress, of the type common on the streets of the Saudi capital, Riyadh. But he expresses views that would earn him immediate arrest if he set foot there.

The country, he tells a visitor, is on the verge of collapse, and a number of factors -- intensifying violence, conflict within the royal family, economic crisis -- could soon bring it down. "This is a crippled and corrupt regime," he declares. "I think the next few months are crucial."

His callers tonight are in complete agreement. A man from Jiddah phones in to denounce the "shameful acts of the royal family." A man who says he is a policeman complains about the lack of pay and equipment and says police are ordered to forgo fighting drugs and crime to focus on protecting the country's rulers. And a woman who identifies herself as "Reform Lover" takes a moment to praise Islah as "the voice of freedom."

Faqih is a slight man with a neatly trimmed beard, wire-rimmed glasses and a soft handshake. While he doesn't lack self-confidence, he sounds a little amazed as he recounts his rise from little-known exile to a sounding board for a nation's grievances.

He was already a successful surgeon when at age 30 he began dabbling in dissent. At first he wrote letters about unemployment and other social issues to friends who were close to the powerful interior minister, Prince Nayef. That was the accepted way, he says -- confidential, friendly, constructive. The letters, he says, were ignored.

After the Persian Gulf War, he and other reformers went public. There was a 12-point petition in 1991, followed by a 44-page program of reform the following year. Then the government cracked down. Faqih was among 18 academics and professionals imprisoned in 1993. He was released after four weeks, and six months later left the country with his wife and four children.

North London, the place where Karl Marx settled after fleeing continental Europe 150 years ago, is now nicknamed "Londonistan" for the many political exiles from the Muslim world who have taken up residence here. "First, it is the capital of the world in terms of media," says Faqih. "Second, the British are very subtle and stable. They deal with facts, and they are not influenced by politics, not influenced by emotions."

The first years were difficult. He and a fellow exile, Mohammed Massari, founded a small organization. But Massari was a high-profile activist who made common cause with extremists. Faqih says he himself wanted a lower profile and more control. While Massari has appeared at public events honoring the purportedly glorious achievements of the Sept. 11 hijackers, Faqih has avoided such platforms.

In 1996 he formed his own group, the Movement for Islamic Reform in Arabia, on a shoestring budget. He insists his vision of a Saudi Islamic republic is benign: power-sharing, accountability, judicial independence, freedom of expression and freedom of assembly are his watchwords. "We honor the common belief of the nation, which is Islam, but we are against the monopoly of interpretation of Islam," he says.

But he has not totally avoided contact with al Qaeda. He became friends with Khalid Fawwaz, a Saudi dissident who in effect functioned as bin Laden's London-based spokesman in the 1990s. Following the 1998 car bombings of U.S. embassies in Kenya and Tanzania, Fawwaz was arrested under an extradition request from the United States. Faqih says he visited him in prison and helped look after Fawwaz's wife and children.

At the trial of four suspects in the bombings, it emerged that Faqih's credit card had been used to purchase a satellite phone that Fawwaz passed on to bin Laden, who allegedly used it to help plan the attacks.

Faqih says a merchant who did business with both him and Fawwaz mistakenly credited the purchase to his account. "The authorities know all the facts," he says. A British government spokesman who spoke on condition of anonymity could not confirm his account.

While Faqih says he advocates nonviolence, he blames "extreme American arrogance" for bringing about the Sept. 11 attacks. And besides, he concedes, "support for al Qaeda is so immense in my country right now that it would be politically incorrect to denounce them."

The Internet gave Faqih a new means of communication, the cell phone another. People in Saudi Arabia can buy cell phone cards that allow them to make anonymous calls. Faqih established a Web site and began posting Saudis' comments and complaints, creating an interactive platform for discussion and debate.

But the real breakthrough came last year when he started the nightly radio broadcast. Nearly 60 percent of Saudi families own satellite dishes, he says, and they have become a prime-time audience for the broadcasts, which can be heard on satellite television.

"This regime survives on secrecy and hypocrisy," he says. "With the radio we broke the barrier of secrecy and we created a means for people to speak not just to us, but to each other."

The extent of his newfound influence was apparent last fall when his call for public demonstrations in Saudi Arabia for reforms brought out protesters and led to hundreds of arrests. This further raised his profile and made him a champion to fellow dissidents of many political stripes.

"Although I disagree with him on many things, I admire his courage and his values," says Ali Ahmed, director of the Washington-based Saudi Institute and a secular critic of the royal family who says Faqih's broadcasts have been groundbreaking.

"He is a pioneer in this sense," says Ahmed. "He has elevated the ceiling of free expression in Saudi Arabia and all over the Middle East, and he has become one of the most popular figures in the country."

Ahmed says Saudi officials are using terrorism as an excuse to attempt to crack down on Faqih and other reformers. "The problem isn't Saad al-Faqih," he says. "The real problem is the Saudi government."

'One Little Mosquito'

"Do you know how you get malaria?" asks Ferej Alowedi, deputy head of mission of the Saudi Embassy in London. "One little mosquito carries the disease. And that's the way we look at al-Faqih. He's just one little insect, but he can do great damage."

Saudi officials say they have been monitoring Faqih's activities ever since he left Riyadh a decade ago. They contend he has been involved in numerous illegal activities, collecting money for terrorist causes and inciting violence. They keep tapes and transcripts of his Islah broadcasts and material from his Web site, saying he has urged listeners to take revenge for alleged crimes against dissidents by assassinating members of the royal family, including Crown Prince Abdullah and Prince Nayef, the interior minister. Faqih's Web site has posted messages from the Voice of Truth, a militant group, offering 1 million riyals (about $267,000) each for the assassination of the country's top six leaders.

British officials here have reviewed the dossier the Saudis have submitted about Faqih's activities, but say that so far they have seen no evidence that would merit his arrest.

"We're well aware of the Saudi concerns over al-Faqih," said a spokesman for the British Foreign Office. "We have got strict laws which prohibit incitement to terrorism but we can only act when those laws are violated. As of today we do not have any violation which we can drill down into." Under British government policy, spokesmen speak on condition of anonymity.

U.S. officials, who have tracked Faqih's alleged al Qaeda connections for several years, have also conveyed concerns about him. Frances Fragos Townsend, meeting with British officials six months ago during her time as deputy national security adviser, voiced concerns about Faqih, according to National Security Council spokesman Sean McCormack.

But Saudi officials say that their new set of allegations should compel the British to take action. They contend that a Libyan intelligence officer, Col. Mohamed Ismael, working under the cover of a charitable foundation in Tripoli, the World Islamic Call Society, came to London at least four times last year to meet with Faqih to discuss a plot to kill Abdullah and other members of the royal family. The sessions were allegedly arranged by Abdurahman Alamoudi, an American Muslim leader based in Northern Virginia.

During the meetings, the Saudis contend, Ismael gave Faqih 1 million euros (about $1.2 million) for his broadcast activities and personal use. At the final session last October, they allege, Faqih gave Ismael the names of four radicals in Saudi Arabia who he said would carry out the assassinations.

By this account, about $1 million was transferred into the country through a travel company in Mecca, which was told the money was for the use of Gaddafi's wife during a pilgrimage there. But the Saudis had monitored the London meetings and were able to arrest the suspected radicals before they could carry out the attacks.

Ismael fled to Cairo, where he was arrested and returned to Riyadh. Alamoudi was stopped by British authorities last August with $340,000 inside a valise and the following month was arrested in the United States when he returned there. He is being held in an Alexandria jail on charges related to cash smuggling.

The Saudis say their information comes from interrogations of Ismael, Alamoudi and 13 others they are holding in the alleged plot. Alamoudi's attorney, James P. McLoughlin Jr., has confirmed that his client "is cooperating with the government in its investigation."

Faqih says the charges are ridiculous. He insists he never met with Ismael, received no money from Libya and did not put the alleged conspirators in contact with assassins inside the kingdom. He says he met several times with Alamoudi, and referred him to a British lawyer after Alamoudi's cash was confiscated at Heathrow Airport. But he says he always kept a distance from the American Muslim leader. "Because he was classified as being too pro-American, it was in my interest not to associate myself with him," Faqih says.

Faqih says he knows he is being watched and that he has to be circumspect: "I am intelligent enough to know that I am surrounded by a crowd of intelligence." Whenever he receives calls from people calling for assassinations, he says, he tries to head them off. "I tell them this is not our approach," he says. "You can change the situation without bloodshed."

Faqih refuses to say where his organization gets its funding. "Much of the money comes from sympathetic individuals," he says. "We are keen for money that is politically, legally and religiously clean. In this dangerous world it's very dangerous to give any details."

Saudi officials say they understand that every time they single out Faqih, his stature increases among militants back home. But they stand by claims that the danger is real. "This man has almost no support inside Saudi Arabia," says a senior security official. "But it only takes one person to make a killer or a terrorist."

Last June, Faqih says, two men arrived at his home claiming to be plumbers. When he opened the door, they sprayed him with gas and tried to drag him outside. He says he cried out for help and fended them off with a small stool. The men fled, after one them knifed him in the leg. The British authorities say two men were later arrested for assault but the charges were dismissed.

Faqih says he believes the assault was orchestrated by Prince Nayef, but Saudi officials strongly deny this. One Saudi official said a prince in the royal family had attempted a rogue kidnap operation -- similar to the abduction of Prince Sultan bin Turki, a nephew of King Fahd, in Geneva a year ago -- without the government's knowledge or consent.

After the incident, Faqih says, he was told by British officials that they had issued a strong warning to the Saudi Embassy here. Still, he says: "I don't feel secure. They have a rogue state over there and they have enough money to do these things. I take my precautions."

Saad Faqih, who lives in London, is under increasing pressure from Saudi Arabia. Saad Faqih broadcasts a live, three-hour radio show from London that is received in Saudi Arabia.