No wonder Seven Pillars of Wisdom - indeed, all of T E Lawrence's work - now tops the reading list of almost every senior US officer in Iraq. Long after his legend was established in Arabia and Damascus and at the Versailles Treaty negotiations - almost 90 years after he realised that his promises to his Arab allies were to be broken by Britain's adherence to the Balfour Declaration - Lawrence's wisdom is now serving to guide (and no doubt misguide) the Americans, who have walked into the hell-disaster of Iraq with no idea of how to retreat. If only, I say to myself each time I arrive in Baghdad, the Americans had read Lawrence before they invaded.

It's not just his experience of betrayal that is of importance. Lawrence's promise of independence to the Arabs who had promised to fight the Ottoman Turks as allies of Britain proved as false as the US pledges to bring freedom, security and democracy to the Iraqis. If recent research has shown that he was partial to Zionism, he never failed to reflect on the treachery that he had unwittingly committed against the Arabs. Britain's support for a Jewish homeland in Palestine was a promise made at the height of the 1914-18 war, when Britain was desperate for Jewish support. And Lawrence's promise of freedom to the Arabs was made when the United Kingdom was desperate for Arab support against the Turks. Promises are meant to be kept. Lawrence's, of course, were not.

There is something painfully self-absorbed about Lawrence of Arabia. His obsessive wearing of Arab gowns - his preparedness to be photo graphed as an Arab - and his constant iden tification of himself with Arabs suggest a man whose politics had taken on a distinctly personal, almost theatrical role. Even at Versailles, and we have only to look at the photograph of him as he stands next to the Arab delegation in Paris, he chose to wear an Arab keffiyeh headdress. Seven Pillars of Wisdom is an epic of literature, but it is also the story of a deeply distressed man whose depression eventually turned him into a cynical figure who tried to hide his identity (not very successfully, it is true) among the humble aircraftmen of the RAF.

Yet his wisdom did not desert him after the 1914-18 war. When insurgents staged a rebellion against the postwar British occupation of Iraq in 1920, Lawrence dispensed advice in the pages of London newspapers that the Americans (and the departing British) should have read before they staged their illegal invasion of the same country in March 2003. Although on a far smaller scale, the 1920 insurgency was an almost fingerprint-perfect forerunner of the present Iraqi conflict. British troops that were assured they would be greeted as liberators found that their supposed beneficiaries were far from happy to see them; Arab-Ottoman soldiers who waited to join the Allied side were abused in prison camps. When the first British officer was killed outside Baghdad, the Brit ish army besieged the Sunni city of Fallujah with field guns and later surrounded the Shia city of Najaf, demanding the surrender of a militant Shia cleric. British intelligence in Baghdad informed the war department in London that insurgents were crossing the border into Iraq from Syria. And Lloyd George, the British prime minister, assured the House of Commons - at a time when the British were tired of sacrificing their soldiers in Meso potamia - that if UK and empire forces were to withdraw from Iraq, there would be civil war.

Lawrence had much to say about this now familiar scenario, not least the casualties inflicted by the occupying forces. In 1920, he estimated that the British had killed "about ten thousand Arabs in this rising. We cannot hope to maintain such an average."

As a result, the British turned to air power to suppress the insurgents. Lawrence wrote a letter to the Observer, describing how "these risings take a regular course. There is a preliminary Arab success, then British reinforcements go out as a punitive force. They fight their way (our losses are slight, the Arab losses heavy) to their objective, which is meanwhile bombarded by artillery, aeroplanes or gunboats." But he had an irritating cynicism bordering on black humour - its initial appearance can be faintly observed in Seven Pillars - which could make him appear not just unattractive, but positively sadistic. "It is odd that we do not use poison gas on these occasions," he wrote in the same letter. "Bombing the houses is a patchy way of getting the women and children, and our infantry always incur losses in shooting down the Arab men. By gas attacks the whole population of offending districts could be wiped out neatly."

If this was sarcasm, it was cruelly inappropriate, although, after a war in which the major powers of Europe had all used mustard and chlorine gas in the trenches of France - and, though few realise it, in the Palestine campaign against the Turks as well - this may not have appeared as vicious a tactic as it does to us today.

Far more acerbic were his later comments in 1929 in an article he submitted under the entry of "Guerrilla" in the 14th edition of the Encyclopaedia Britannica. Writing of Arab resistance to Turkish occupation in the 1914-18 war, he asks of the insurgents, some of whom he led, ". . . suppose they were an influence, a thing invulnerable, intangible, without front or back, drifting about like a gas? Armies were like plants, immobile as a whole, firm-rooted, nourished through long stems to the head. The Arabs might be a vapour." Lawrence uses the horror of gas warfare here as a metaphor for insurgency, but who can disagree with his conclusions? To control the land they occupied, the Turks "would have need of a fortified post every four square miles, and a post could not be less than 20 men. The Turks would need 600,000 men to meet the combined ill-will of the local Arab people. They had 100,000 men available." The "fortified posts", of course, prefigure George W Bush's "surge", which needed 600,000 men to meet the combined ill-will of the Iraqi people but had only 150,000 available.

Accurately predicting al-Qaeda's modern-day use of the internet, Lawrence wrote that "the printing press is the greatest weapon in the armoury of the modern (guerrilla) commander". For insurgents, "battles were a mistake . . . Napoleon had spoken in angry reaction against the excessive finesse of the 18th century, when most men almost forgot that war gave licence to murder." And Lawrence, realising in his canny way that he was right, continued with these frightening predictions:

Rebellion must have an unassailable base . . . in the minds of men converted to its creed. It must have a sophisticated alien enemy, in the form of a disciplined army of occupation too small to fulfil the doctrine of acreage: too few to adjust number to space, in order to dominate the area effectively from fortified posts. It [the insurgency] must have a friendly population, not actively friendly, but sympathetic to the point of not betraying rebel movements to the enemy. Rebellions can be made by 2 per cent active in a striking force, and 98 per cent passively sympathetic . . . Granted mobility, security . . . time, and doctrine . . . victory will rest with the insurgents, for the algebraical factors are in the end decisive, and against them perfections of means and spirit struggle quite in vain.

If insurgents represent a "vapour" more powerful than that which comes from the mouths of politicians (I suppose the "fortified posts" would represent Donald Rumsfeld's useless military "lily pads" in the Iraqi desert), then the Anglo-American invasion force should have known in 2003 that Lawrence's prophecy doomed them the moment a serious military resistance movement opposed Iraq's occupation. In the Sunday Times in 1920, Lawrence might have been addressing his words to George W Bush or Tony Blair. "The people of England have been led in Mesopotamia into a trap from which it will be hard to escape with dignity and honour," he wrote. "They have been tricked into it by a steady withholding of information. The Baghdad communiqués are belated, insincere, incomplete. Things have been far worse than we have been told, our administration more bloody and inefficient than the public knows . . . We are today not far from a disaster."

One is left gasping at the prescience of such words. For is this not exactly what has happened to us in Iraq since 2003: the lies, the insincerity, the false claims of "mission accomplished" and success when we are trapped in the sands of Iraq, our "statesmen" all the while withholding in formation while they pretend we can retreat with honour? "The Arabs," Lawrence wrote in another letter in 1920 - this one to the Times - "rebelled against the Turks during the war not because the Turk government was notably bad, but because they wanted independence. They did not risk their lives in battle to change masters, to become British subjects . . . but to win a show of their own. Whether they are fit for in dependence or not remains to be tried. Merit is no qualification for freedom."

By 1930, a totally dispirited Lawrence, poorly disguising himself as an RAF dogsbody, was writing to an American anthropologist, who wanted to meet him to discuss the Arab world, with a pitiful sense of humour and a mock-schoolboy touch that showed just how far his spirit had deteriorated since the 1920s.

Dear Mr Field, I hope you are colossally rich, so that the cost of coming all the way to this misery of Plymouth (the last or first town of England, according to your hemisphere) will mean nothing to you. I'm a fraud as regards both the Middle East and archaeology. Years ago I haunted both, and got fairly expert, but the war overdosed me, and nine years ago I relapsed comfortably into the ranks of our Air Force, and have had no interests outside it since. Nine years is long enough to make me out of date but not long enough to make my views quaint and interestingly archaic. I have forgotten all I knew, too.

I have seen this letter in Lawrence's own hand and thought at first that he described himself as a "friend" of the Middle East, but alas - forever demeaning himself - he did indeed write "fraud". His letter goes on to advise Field how to recognise him at Plymouth Station. "Look out for a small and aged creature in a slaty-blue uniform with brass buttons: like an RAC scout or tram driver, perhaps, only smaller and shabbier."

It is perhaps as well, reading Seven Pillars, to remember that this wonderful, imaginative, brave man could, in just a decade, reduce himself to such penury and self-destruction. Only his beloved motorbike remained to him. And that, of course, was his final nemesis.

© Robert Fisk, 2008 "Seven Pillars of Wisdom" by T E Lawrence is published by Vintage Classics (£9.99)