Whatever happened to British grit and steel? Given the self-doubt and hand-wringing surrounding the deaths of three British soldiers in Afghanistan on Sunday, which took the number of British troops killed there since 2001 to the symbolic but otherwise meaningless 100 mark, it would be small surprise if the Taleban is bolstered in its belief that it can outlast - if not outfight - Britain's troop commitment to Helmand.

Despite media fascination with the 100 figure, British casualties in Afghanistan are low compared to those of many army campaigns in the past 50 years. Although it is somewhat distasteful to examine the statistics of dead sons, husbands and brothers, the numbers require some assessment for their relevance to be understood.

When compared with the 1,109 British troops killed in Korea; the 763 who died in Northern Ireland between 1969 and 1997 (146 British security force members were killed there in 1972 alone, of whom 103 were soldiers); or the 255 who died in the three months of the Falklands conflict, the six-year toll in Afghanistan gains some kind of perspective. (Other key figures are the 67 British civilians slain in the twin towers and the 52 killed in the London bombings three years ago.)

But even these comparisons are meaningless when removed from the wider context. Some 20,000 British and Commonwealth troops were killed on the Somme in a single day, July 1, 1916. The nation remained stoic in supporting another two years of fighting.

By contrast, Somalia, where 18 US servicemen died during an arrest mission in 1993, leading to a prompt US withdrawal, showed that sometimes only a small number of casualties is needed to reverse government policy.

So why are we so convulsed by the 100 dead in Afghanistan?

Consent is the key. The Government needs public consent to commit troops to kill and die in faraway lands. When people are accurately informed about the reasons for an army's deployment and the possible benefits and debits, a democracy's citizens can draw up their own balance sheet to decide whether the price is worth paying. In wars for national survival (the First and Second World Wars), conflicts close to home (Northern Ireland) or short wars that capture a sense of national identity (the Falklands), tolerance of dead soldiers is high.

Yet to date the Government has failed to state clearly its case for Afghanistan. Given the muddled and often contradictory mission statement, it is small wonder that the public is confused about why it is losing men there. Reconstruction? Reconciliation? War fighting? Drugs? Democracy? A bit of everything, apparently.

The Government has also failed to obtain the unconditional consent of the Army itself, traditionally a “can-do” organisation. British troops and airmen have become rather less convinced by their role in Afghanistan. Tommy Atkins, on realising that he is paid less than a traffic warden; that his wife may leave him because of the repeated operation cycles caused by overstretching; and that his family's accommodation is shoddy, is asking himself is it worth it? (He would ask a lot more questions if he knew more about the venal and corrupt Afghan Government that he has been sent to support.) The age of “theirs not to reason why” has not survived contact with the internet, and soldiers are better informed and more questioning than they were.

Ironically, the Government's efforts to support its forces by naming and honouring each dead soldier at Prime Minister's Questions has added to the drip-drip of failure attached to the mission, while appearing hypocritical to underresourced soldiery.

A dramatic overhaul is needed if the Afghan mission is not to collapse through lack of resolve. The Government should abandon its funereal approach to each casualty, regain confidence in its convictions and remind us that the West's failure to attend to Afghanistan between the pullout of Soviet forces in 1989 and the deployment of coalition troops there in 2001 led to a situation that directly affects our security.

Western intelligence agencies estimate that at least 10,000 men went through al-Qaeda training camps established in the country during the Taleban's five-year rule. Afghanistan became a platform for terrorist attacks against us, and the ideas and expertise taught in these camps led, directly or indirectly, to thousands of deaths in Tanzania, Kenya, Bali, New York, Spain and London. Ignoring the country or, worse still, abandoning it, is not an option. It will not ignore us.

Until that argument gains weight in the mind of the British public, the death of each of our soldiers in Afghanistan will continue to take centre stage in an opaque but emotional plot, and be subjected to exactly the kind of confused interpretation that the dead fighter's mission seeks to avoid. It is bad to lose a war, but even worse to lose it through ignorance.

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