The group of anonymous grunts who tethered the stars'n'stripes to a length of waterpipe and raised it over Iwo Jima would have had no inkling of the significance of their act.

However, to an America emotionally exhausted and almost financially bankrupt by the fight against the Japanese, the image was the morale boost credited with turning the course of the war.

Director Clint Eastwood has meticulously crafted the sequence of events to feature not only the nobility of the Marines but the White House war machine's ruthless manipulation of the flag-raising to boost its coffers.

In February 1945, a vast American flotilla launched a full-frontal assault on Iwo Jima, a barren sulphurous island (Iceland was used for the action scenes), its black sand riddled with foxholes containing 12,000 Japanese defenders.

On the fifth day, a press photographer snapped five Marines and one Navy Corpsman raising the flag above the freshly-captured Mount Suribachi.

The image of the tableau was flashed around the world and, to capitalise on the wave of sentiment the photo inspired, three of the "flag-raisers" (the rest died in combat within days) were brought back to the states to campaign for war funds.

The story appears straightforward enough until small anomalies began to emerge. It wasn't, in fact, the first "flag-raising" - it was a second, staged one. One of the Marines identified is the wrong one.

However, the publicity machine doesn't want anything to disturb the raising of war bonds so any disparities are quietly airbrushed out of the picture, much to the distaste of the men themselves.

Eastwood isn't afraid to tackle the thornier issues thrown up by the flag-raising episode but he deals with a complex set of events in a balanced, honourable manner.

His main players don't occupy the highest place in the Hollywood firmament - Paul Walker is best known for car crash movies, Jamie Bell was Billy Elliot and Ryan Phillippe is the second division star of the likes of Crash and Gosford Park.

Adam Beach is terrific as Ira Hayes, the publicity-shy Native American who hits the bottle after shameful treatment as a flag-raiseer (one political heavyweight refuses to shake his hand while he's refused service in a racist Chicago bar).

What emerges is the simple decency of these men who, for all their human flaws, embody the virtues of a type of man who "fought for their country but died for their friends."

Ultimately, Eastwood's magnificent epic is not about heroism (although there's plenty of that) but about America's inability to apply the values - honour, equality, justice - it fought for abroad at home.

Tim Evans