For years Remembrance Sunday was about honouring the dead of past world wars. That is still an important part of ceremonies to be held in Britain this morning. Rarely, however, have the sacrifices of the past been more closely entwined with those of the present. On foreign fields in Afghanistan, the toll of dead and injured British soldiers is rising alarmingly.

The stories of sacrifice from Afghanistan are humbling. Today we carry an interview given before his death by Staff Sergeant Olaf Schmid, an army bomb disposal expert who defused dozens of improvised explosive devices. He should have been home this weekend with his family. Instead, he was killed on his last operational day. The tribute of his wife, Christina, that he was an “absolute hero”, was painfully moving.

All wars have pivotal moments. Last Tuesday’s incident, in which five British soldiers were shot dead by an Afghan policeman they had been training, may be one. Suddenly, all the doubts about the war were encapsulated. The soldiers died in an act of treachery by an Afghan colleague. Do the Afghans want us there and, if not, why are we sacrificing lives to prop up the corrupt government of Hamid Karzai? Given that the strategy of the allies in Afghanistan is to hand over the security of the country to the Afghans, does it have the faintest hope of succeeding?

Every death and injury increases doubts about the war. The prime minister’s central argument for our presence in Afghanistan, to make Britain’s streets safer, is questioned. Indeed Gordon Brown has failed to win the argument on why our troops are there and whether they are well equipped. The result is growing public scepticism and rifts among politicians. Kim Howells, Labour chairman of the parliamentary intelligence and security committee, says the best way to keep British citizens safe is to wind down the military presence in Afghanistan, using the money to beef up anti-terrorist surveillance in Britain. Sir Paul Lever, chairman of the Royal United Services Institute, said that UK terrorism was “principally a home-grown phenomenon” and Britain was the “real front line” in the fight.

So far the political establishment is holding firm in its belief that we should continue to fight in Afghanistan. But it is increasingly divided on the strategy, as the US administration takes an interminable time to make up its mind on its next move.

There are no easy answers. Lord Ashdown’s view is that failure in Afghanistan “would mean the inevitable collapse of the Pakistan government and jihadi hands far too close to nuclear weapons”. Others take the opposite view to the former Liberal Democrat leader. They say the presence of foreign troops in Afghanistan has destabilised Pakistan and that their departure might help the government.

Few believe the Afghan war is winnable. The debate is over the best containment strategy. Generals are drawing up plans to shift to defending only the large centres of population in central Helmand, in effect abandoning other areas to the Taliban. Many may see that as a retreat and the first steps towards a humiliating withdrawal. These are tough decisions for commanders and politicians. To leave Afghanistan precipitately would be a big blow for the West and a moral victory to Islamists. That could have severe repercussions in Britain. But to soldier on is not good enough. We need a better strategy that the public can get behind. Otherwise even more wooden crosses will be added to the fields of remembrance, with little to show for their sacrifice.