The Mirror explores the CIA's nightmare scenario
Special Report by Stephen White
In an airy office of the Central Intelligence Agency in Washington a note pinned to the wall reads simply: "Think the unthinkable."
It is a lesson every CIA agent learns in the first few weeks of training. Since September 11 it is a mission statement that has been practised in the agency's "situation rooms" a thousand times.
Agents have dreamed up every conceivable scenario - from attack with a nuclear bomb the size of a suitcase to refugees poisoned with smallpox sent to infect coalition troops.
But one scenario above all fills them with dread. While he is isolated in Afghanistan Osama bin Laden may be a hero to the disaffected of the Muslim world but he is still a remote and distant figure.
What if he were to escape through a high mountain pass? He could be less than 700 miles from Mecca, Islam's holiest place. And no coalition forces could enter the city - which is barred to non-Muslims - without an uprising in the Islamic world.
If bin Laden could reach the Saudi Arabian city, could he reclaim the country that stripped him of his citizenship and drive the "infidels" from the Middle East?
Like the prophet Mohammed, could he stand before the black monolithic stone in the Great Mosque and return the states of the region to an Islamic brotherhood?
His supporters believe he could - that the man dubbed the world's most wanted terrorist could challenge all the forces set against him.
This nightmare scenario is very remote. The Saudi authorities could not tolerate his presence and they know the West would not tolerate allowing him to remain in Mecca.
For the Saudis that would be suicide. If they did nothing, bin Laden's standing in the Muslim world would soar and the government would sign its own death warrant through inaction.
Holy: Nearly a million pilgrims throng the Great Mosque in Mecca.
The sanctity of Islam's holiest site would not stop them from taking action. In 1980 some 500 Shiite Muslims loyal to Iran's Ayatollah Khomeini took over the Great Mosque, capturing thousands of pilgrims inside.
The Saudis responded with a bloody assault, with troops ordered to take no prisoners.
In the capital Riyadh, gleaming upmarket Toyota four wheel drives cruise the immaculate streets.
Men in pristine white robes hand the keys to parking attendants outside five-star hotels.
Westerners window-shop in the gold markets and the electronics stores selling the latest gadgets.
They visit their hosts in the desert where Saudis remember their Bedouin roots, reclining on expensive carpets in carefully erected tents complete with electricity and sumptuous banquets. Wealth appears to be everywhere.
On the outskirts of the city an American eagle is the symbol of the US Third Army Command Centre.
But this is the country that gave birth to 15 of the 19 terrorists who carried out the World Trade Center and Pentagon attacks.
It is the country that gave birth to Osama bin Laden.
And it may be this kingdom is a key to the present global conflict every bit as vital as the Israel-Palestine conflict.
It was the Saudi royal family who handed Osama bin Laden's father contracts for roads, hospitals and palaces, helping him to build up the huge construction firm that when he died left Osama a rich man.
But it was the same royal family who turned their back on Osama and his battle-hardened Islamic warriors who had fought the Russians in Afghanistan.
The young idealist offered to protect the country with his men when Iraq invaded Kuwait. Instead Saudi's rulers turned for protection to the US and its hi-tech firepower.
Now the Saudis will not allow the Americans to use their bases in the country to attack Afghanistan. They snubbed Tony Blair on his whistlestop tour of the Middle East.
But they still allow the US to use their command bases and still invest billions in the West.
Bin Laden believes that even allowing the "infidels" on to holy soil is an act of betrayal against the Muslim faith.
His passion is felt not only by those who share his religous fervour but even by ordinary Saudis, who at mosques in Riyadh were told the US attacks on Afghanistan were "the most awful crime ... Western crusader terrorism".
Devoted: Wahabite bin Laden
Bin Laden's brand of Islam is Wahabism, a puritanical form of the religion that is growing throughout the Middle East.
Wahabi fighters are among the most hardline guerrillas in the Russian state of Chechnya.
Saudi money has built more than 1,600 mosques across the world in the last decade and countless Islamic schools and colleges. In Egypt new mosques financed by Saudis are springing up all over Cairo.
The country has put cash behind Muslim struggles in Kashmir, Palestine and Kosovo and more than £400million towards the rebuilding of Bosnia.
But Wahabism does not sit easily with the lifestyle of the rulers of Saudi Arabia.
The country controls about 25 per cent of the world's oil reserves. Oil makes up 80 per cent of its exports.
But without the oil revenue the economy is on the verge of collapse. And that could lead to the overthrow of its rulers.
In the past 20 years economic growth has slowed to an average 0.2 per cent a year. Unemployment has risen to 18 per cent.
The birth rate has exploded, 43 per cent of the 15million people are under 15, education for many is almost non-existent and the annual income per head, once equivalent to America's, has fallen to £5,000. Saudi Arabia has turned to huge foreign borrowing to maintain its economy.
But still money is pouring into the desert sands.
Many Saudis work in state owned industries which are overmanned, inefficient and in some cases just pointless.
The royal family - most in their 60s and 70s, although there are thought to be 30,000 members of the royal household on the payroll - soaks up as much as 40 per cent of revenues.
This year youths rioted at a new shopping centre in the capital and the unrest is a fertile breeding ground for those like bin Laden who believe Wahabism provides the answer.
In universities and mosques in Saudi and other Muslim countries the creed grows that a brotherhood of Islam will cure the region's woes.
Bin Laden is a devoted Wahabite, as are the Taliban.
It was Wahabites who drove the Turks out of the Arabian peninsula.
Bin Laden believes the Westerners who "infest" Saudi Arabia should be driven out and that from there he can fight back against the "infidels". Saudi Arabia may impose the strictures of Islamic law, including public flogging and executions, but in al-Qaeda's eyes it has become corrupt and pro-Western.
Bin Laden has ignited a passion for his beliefs among those who are not on the gravy train in the kingdom.
Saudis are flocking to his side. Ten thousand are believed to have trained in al-Qaeda's camps, drawn by a man they believe can make their nation and the Arab world great again.
A week after the attacks on the US 79-year-old King Fahd, who had a severe stoke in 1995, flew to Switzerland for treatment. In Riyadh there is palace talk of disputes and mistrust.
Ailing: King Fahd
Fahd's half-brother, 77-year-old Prince Abdullah, is the heir apparent but he is opposed by the king's seven full brothers.
The future of them, their dynasty and their country is by far from certain.
They stripped bin Laden of his citizenship in 1994.
It is not a slight he or his followers are likely to forget.
THE holy city of Mecca in Saudi Arabia is the birthplace of the Prophet Mohammed.
It has been the spiritual centre of Islam since the 7th century and all Muslims pray facing it five times a day.
One of the five pillars of the religion requires every believer who can afford it to make a pilgrimage to Mecca at least once in their lives.
Nearly two million faithful, many in their 70s and 80s, make the trip every year in Zuul-Hijja, the last month of the Muslim calendar.
About 20,000 British Muslims go, like the rest, to have their sins washed away.
The most holy site in Mecca is the al-Haram Mosque, within which is housed the Black Stone - or Kabah. During the pilgrimage, the faithful circle the Kabah seven times and try to touch the rose stone held inside it.
The pilgrimage ends with a retracing of the journey of Mohammed, who delivered his last sermon at Mount Arafat, near Mecca, in 632AD.
Mecca is strictly off limits to non-Muslims.
WAHABISM was founded by Mohammad Ibn Wahab, who was born in 1703 near Riyadh.
As a protest against loosening moral standards he preached an extreme fundamentalist form of Islam, interpreting the Koran in its most severe form, including relegating women to an inferior role. He also rejected all foreign influence.
His successors conquered the greatest part of what is today Saudi Arabia.
Opposed to any form of idolatry, they destroyed the shrines of Kerbala in 1802, Mecca in 1803 and Medina in 1805.
But they were defeated in 1811 by the army of the Egyptian Ottoman ruler Mehemed Ali, who acted on behalf of Turkey and was armed with European weapons.
Wahabism remained a force in the area, relying on "warrior preachers" known as the Ikhwans, which means brothers in Arabic.
Under the leadership of Ibn Saud they reconquered Mecca and Medina, which in 1932 led to the creation of the modern kingdom of Saudi Arabia.
THE SAUDI ROYAL FAMILY
HEAD of the royal family is King Fahd, 79, who in 1995 had a stroke which left him virtually unable to speak.
The question of who will succeed him has plunged the unstable nation into turmoil.
The family are divided into two factions. Largest and most powerful are the Sudairi, the king's seven full brothers, sons of King Ibn Saud.
Standing in their way is the king's half-brother Prince Abdullah.
The king issued a decree giving him the succession but later retracted it.
The family have resorted to violence in the past. In 1975 a disaffected nephew assassinated King Faisal, Fahd's elder brother.
Both sides are bolstering their position by putting family members in key positions.