Instead, the invaders get bogged down in the foetid marshes and broiling deserts; the enemy refuses to run away; soldiers perish in their thousands and Britain suffers one of its worst military defeats.

Even when regime change is finally brought about, the Iraqi people rise in rebellion and are cowed only by a ferocious aerial bombardment. There is talk of chemical weapons and the occupation drags on, draining blood and treasure, year after year.

This may sound like Tony Blair’s nightmare, the worst-case scenario of the looming conflict. In fact, it is the story of Britain’s first invasion of Iraq and provides an uncomfortable echo of the events unfolding today.

Then, the soldiers were clad in First World War uniforms; Baghdad was part of the Ottoman Empire and the enemy were Turks. The threat to use poison gas came not from President Saddam Hussein, but from Lawrence of Arabia and Winston Churchill. The most strident voice urging aerial bombardment to put down Iraqi insurgents was that of Arthur “Bomber” Harris, who would later use those methods to reduce Dresden to rubble.

The Mesopotamia campaign of 1914-1915 was one of the least glorious chapters in British military history, which is why imperial historians made strenuous efforts to forget it. Even Saddam Hussein does not celebrate Britain’s disaster in his propaganda, for the defenders of Baghdad were not Iraqis but Turkish imperialists. This is one chapter of history that Mr Blair will not be evoking in the coming days; for this, as General George Gorringe bitterly recalled afterwards, was “the bastard war”, a war nobody much wanted to fight, and few cared to remember, then or now.

British forces landed at Basra in November 1914 to protect the Persian oilfields against the Turks and their German allies. “I do not care under what system we keep the oil,” Arthur James Balfour, the Foreign Secretary, would declare. “But I am quite clear it is all-important.”

At the head of the army marched Major-General Charles Townshend, amateur violinist, ambitious extrovert and military incompetent. Having secured Basra, the over-confident Townshend pushed north up the Tigris, determined to take Baghdad and restore British prestige in the Middle East after the bloody debacle of Gallipoli. As the soldiers trudged through the soggy heat, one Indian trooper was heard to remark: “It passeth my understanding why the British Government should be interested in this Satan-like land.”

The gung-ho British press referred to the campaign as the “Mesopotamian picnic”, but as the men marched through the flat, fly-blown marshland, a Canadian soldier observed pithily: “This ‘ere is the land of sweet F-all with a river up it.”

By the time they reached Cstesiphon, 30 miles south of Baghdad, the British were already depleted, dispirited, exhausted and outnumbered. A well-entrenched and reinforced Turkish army pushed them back, and the dreadful retreat began. By December 1915 the British had regrouped at the village of Kut al Amara, where they were immediately surrounded and besieged.

The rations ran out after 22 days, but the siege of Kutal Amara would last for nearly five excruciating months. The men were reduced to eating pack animals, ravaged by heatstroke, cholera, dysentery and scurvy. Every attempt to break out failed. T.E. Lawrence was dispatched to see if he could bribe the Turkish commander into retiring, but without success, and Townshend appears to have suffered a nervous collapse. Finally, in April 1916, he spiked his guns and raised the white flag, but not before the British army had suffered 23,000 dead and wounded.

Eight thousand survivors were taken prisoner and paraded through the streets of Baghdad and Tikrit, Saddam Hussein’s home town, where the captives were treated with notable brutality. One soldier recalled the march: “Some were thrashed to death, some robbed of their kit and left to be tortured by the Arabs. Men often fell out from sheer weakness.”

Three-quarters of them died, but not Townshend, who lived out the war “in comfortable captivity” at the Pasha’s palace in Constantinople.

Explore World News

• Iraq News

• US & Americas News

• Europe News

• Middle East News

• Asia News

• Africa News

• Ireland News

Times Recommends

• How Colombian military rescued Ingrid Betancourt
• 'Pregnant man' gives birth to baby girl
• Hitler finally returns to Berlin