BOOKS about the fighting in Afghanistan threaten to become ten-a-penny. Not only does Nato's campaign against the Taliban look increasingly like a rerun of the Thirty Years War but it is being covered relentlessly by an army of embedded journalists and commentators.

Whether they are able to shine a light through the fog of this foggiest of wars is another matter. After being embroiled in a fierce fire-fight during the battle for the town of Musa Qala in December 2007, journalist Stephen Grey found the strength - and the inspiration - to offer his own opinion: "Another battle for another pile of rubble in a far-off place whose name the world will soon forget." A listening special forces gunner simply replied: "Roger that!"

That moment sums up the underlying message of Grey's enthralling and unvarnished account of a battle which would struggle to find a place as a footnote in any broader history of warfare. The actual fighting lasted only days, and while the operation was a success, from a short-term military point of view, it revealed a hornet's nest of problems which are still extant in Helmand province.

Fortunately for those who want to understand why 7000 plus British soldiers are deployed in Afghanistan, with more to come later in the year, Grey is neither a cheerleader nor an outright cynic. Like all good journalists, he starts with an open but inquiring mind and, better still, he conforms to the philosophy of William Howard Russell of The Times, the godfather of all war correspondents, who uncovered unpalatable truths in the Crimea and warned his editor that he "could not tell lies to make things pleasant'".

In making his voyage of discovery - for so Grey's experience will seem to many readers - he is unsparing in his revelations of the head-in-the-sand thinking that characterises so much British policy in Afghanistan. The tough-minded ambassador Sir Sherard Cowper-Coles spoke of naivety and "misplaced optimism", and Brigadier Andrew Mackay, the officer commanding 52 Brigade, arrived in the country to discover that senior officers "were making it up as we go along". Closer inspection showed that overstretched British forces were unable to hold territory and that their equipment was often useless. Helmand is a huge area, roughly the size of Switzerland, but, astonishingly, Mackay had only seven workhorse Chinook helicopters at his disposal and on a good day only four might be serviceable.

As Russell told his readers in 1854 when he first arrived in the Crimea, this is no way to run a war. But this is Afghanistan at the end of the first decade of the 21st century, and Grey has made it his mission to inform, criticise and give praise where praise is due. During the course of putting this account together, he has talked to many of the main players, not just senior commanders and diplomats but also soldiers at the sharp end, and it is their testimony which gives the book its edge.

No one who reads the account of the death of Sergeant Lee Johnson, 2nd Yorkshire Regiment, can fail to be moved by Grey's clear-eyed and unforgiving description of the incident. Johnson, an experienced soldier, had a premonition that he would not survive the operation and so it proved: his poorly armoured Vector vehicle hit a mine and he was killed instantly in the blast, one of 26 soldiers killed in action during 52 Brigade's six-month deployment. Later, the author visits Johnson's family in the north of England and the book ends with an absolution of sorts.

The chapters dealing with the fighting for Musa Qala form the narrative's hard core, and Grey proves more than adept at describing the confusion and contradictions of that action, which was fought to free the town from Taliban domination. He neither over-simplifies nor over-grandioses and manages to get across the chaos and the hellish fear experienced by those under fire at the sharp end of battle. There is not much room for glamour here, as with the description of the death of Captain John McDermid, a Highland Fusilier from Glasgow who had volunteered to train the Afghan National Army and was killed in a massive bomb-blast in Sangin's bazaar.

Grey is rightly unsparing in his descriptions of combat and quite correctly he points to the paucity of equipment that causes so many unnecessary deaths - McDermid's patrol only had one radio and it disappeared when he was blown up - but the book's real beef is the fat-headed approach of the British mission in Afghanistan. Three years ago, when the Helmand operation began, the then defence secretary John Reid claimed that the British forces there would be happy if they left without firing one shot. It did not turn out that way. Instead of eradicating poppy production, assisting with reconstruction and policing the Taliban, a succession of British brigade groups found themselves involved in some of the fiercest fighting since the second world war.

Little of what Reid promised has come to pass and, just as bad, British commanders have had to contend with contradictory political advice and with an administration in Kabul that is at best inefficient and at worst corrupt. An Afghan diplomat told Grey that there could be no improvement as long as president Hamid Karzai was in power because each time a politician was sacked for corruption, he was immediately given another job. "After a while," he added, "you have to ask yourself: why is this man protecting these people?"

Fortunately the book is also inhabited by good guys, one of them being the commander of 52 Brigade. Before Mackay took his force out to Helmand, he knew that he had to rewrite its counter-insurgency doctrine and that lessons had to be learned from a similar campaign fought in what was then Malaya between 1948 and 1960. "Unless we retain, gain and win the consent of the population within Helmand, we lose the campaign," he told his senior officers. "The population is the prize." This was not special pleading but an honest assessment of the realities of life in Helmand. By all means institute measures to neutralise Taliban fighters, but the war would never be won unless it was backed up by firm political and economic resolve. However, for all his brigade's bottom-up successes, he told the author, this broader approach has "not occurred in any substantive or effective manner".

If this is close to a policy of despair, it cannot detract from the courage and endurance of the men and women who put their lives on the line in Helmand province on a daily basis. They are the real heroes of this timely history, and Grey has made a good fist of recording and memorialising their achievements. The great pity is that those efforts have not been matched by sufficient political willpower in Kabul, London and Washington. This is a persuasive and thoughtful account of an unwon war, written in a spare and muscular prose which just manages to keep the author's indignation at bay. My only gripe is the absence of an index, an unforgivable omission in a book which will long outlast the events it recounts.

For every copy of Operation Snakebite sold today on Amazon.co.uk, £2 of the price will be donated to the Combat Stress charity