The Islamic opponents of the House of Saud are fewer than "the fingers of one hand", he states. Those in exile in London are in breach of the sharia law, he says, and their propaganda, conducted from Britain, should cause the British government to "consider the interests'' of Saudi Arabia - a statement of greater resonance in Prince Nayef's courtly Arabic than its translation suggests.
"We are not comfortable with this, because it is taking place in a friendly country with which we have a deep political and economic relationship,'' he observes. "We respect all the laws and the interests of any country, but at the same time we value ourown interests - and any activities against the government of Saudi Arabia will be a key element of our interests.''
It is rare for any senior member of the Saudi royal family to meet a foreign journalist. But during a week of interviews and private conversations with some of the most senior figures in the kingdom, it became clear that there is mystification and deep concern among the ruling elite over widespread reports in the West of an upsurge of opposition to the House of Saud.
For almost three hours, Prince Nayef voiced indignation at what he described as false and malicious writing and offered a forceful defence of the government's political and economic record. He also gave a detailed account of the events that led to the recent detention of 157 radical Islamic activists and the flight of the prominent dissident, Muhammad al-Masari, to London. The Home Office has refused Mr Al-Masari's application for political asylum, but an appeal could allow him to stay for at least another year.
To the Islamist charges against the royal family of corruption, loose living and the abuse of power, he replies: "These shortcomings and mistakes can happen in any society. We are trying to solve our mistakes. I would say that nobody is one hundred per cent perfect.''
In essence, fundamentalists such as Mr Al-Masari challenge the House of Saud's legitimacy as keeper and interpreter of the Islamic way. In turn, Prince Nayef challenges his religious opponents to prove that they are "any more pious Muslims than we are''.At first sight, that would seem to be a tall order.
A 1920s traveller called Riyadh a city where "all that redounds to the glory of man is banned''. Remote, austere and withdrawn from the wider Arab world, its inhabitants practised the Wahhabi variation of Islam, renowned for fervent intensity. Prince Nayef's father, King Abdul Aziz, employed the fiercest Wahhabi warriors, the Ikhwan, to conquer most of the peninsula and to unite the provinces of Nejd and Hejaz in one kingdom in 1932.
In the process they seized Mecca and Medina to win for Abdul Aziz a title inherited by King Fahd, the "custodian of the two holy mosques''. To this day, the religious police patrol Riyadh with sticks and clubs in search of anyone infringing the sharia laws against unveiled women and the consumption of alcohol, while, in the square outside the city's splendid central mosque, beheadings with the sword give regular proof of the sharia's ultimate sanction.
The kingdom founded by Abdul Aziz rested upon three pillars: the ruling house itself, the Wahhabi religious dogmatists of the Nejd and the great merchant dynasties of the Hejaz who traded from the port of Jeddah. At intervals the balance of power and interest shifted as social changes, spurred by a rapid increase in oil revenues, created religious tension between the modern and the reactionary. "Quite clearly,'' says a Western ambassador, "that pattern is being repeated today.''
Prince Nayef says that the Saudi people "respected the need for foreign soldiers'' to come to the kingdom during the 1990-1991 Gulf conflict. But in retrospect it is clear that the upheaval of war set off forces beyond the government's control. The subsequent economic burden - Prince Nayef put the total costs of the Gulf war to Saudi Arabia at $70bn (£45bn) - combined with lower oil prices to pose a serious financial problem. The Saudi government, however, "gives assurances that it will overcome this cr isis''.
After the Gulf war the kingdom's consultative council, the Majlis Al-Shura, was revived. A new system of provincial government was set up and a basic law drafted to codify a legal system hitherto based on a literal reading of the Koran. But another result was a petition by 109 learned religious figures to King Fahd demanding that the House of Saud cleanse itself and impose Islamic orthodoxy anew throughout society and government. Then, in 1993, Muhammad al-Masari, a physics professor, joine d about halfa dozen other Islamist thinkers to form a group which entitled itself the Committee for the Defence of Legitimate Rights and published a manifesto of impeccably fundamentalist dogma.
"This was a religious, not a political question for us,'' says Prince Nayef. Indeed, it is not widely known that the word translated from the committee's title as "legitimate'' or even, in the US, "human'' rights, derives from the same Arabic root as theword sharia. "Legitimate'', to the Masari group, is therefore only whatever is founded in Islamic law.
Prince Nayef, however, says the country's Ulema, or religious leadership, endorsed the government's view that the Islamist campaign was actually in violation of the sharia, which does not endorse the overthrow of rulers. He says his technique with Mr Al-Masari and other activists was to warn, to persuade and to enjoin conformity with the Ulema. Mr Al-Masari, he points out, had been released from detention to ponder the error of his ways when he fled to London. A flow of faxes and telephone calls to Saudi Arabia from the exiles has since renewed the Islamist campaign.
In September, Prince Nayef said, the authorities felt bound to move against preachers who were stirring up gatherings in the mosques of Bureydah, a town north of Riyadh in the fundamentalist heartland of the Nejd. "We detained 157 people,'' he said. "After a while 130 of them admitted they had been enticed into a mistake and asked for a pardon, which was granted. Twenty-seven are still in custody and all of them have connections with organisations abroad which are known to support terrorism - and they have connections with Masari.''
Absolute monarchies, of course, are not accustomed to tolerating challenge, and in Prince Nayef the House of Saud possesses a cultivated absolutist of a vintage that would not have disgraced the Ottomans or the Romanovs. "The Kingdom of Saudi Arabia is capable of facing and destroying these movements,'' he says. He does not waste words on promises of political reform.
Had he heard, I wondered, of De Toqueville's theory that the period of maximum danger for absolutist regimes is the moment they try to liberalise? "We consider,'' the Prince responds smoothly, "that since our establishment as a nation we have already been liberated.''
Tomorrow: Will economic woes bring political change?
Islamists' challenge stirs the House of SaudReuse content