Sunday evenings during harvest are like the slow movement in a sonata. After the nervous Allegro of waiting, the combines pull out of the farmyard. As first reports come in yields high, moisture low a welcome Andante descends. We open a bottle of wine, then settle down to left overs with only the sensitive voices of Matthew Bannister or John Wilson for company, presenting Last Word, the weekly obituary programme.

In the week that eight British soldiers were killed in Afghanistan and 15 in 10 days not one of the obituaries is of a British soldier. Perhaps 18 year olds haven’t done enough in their short lives to merit a slot, but I’ve never heard the obituary of a soldier serving in Iraq or Afghanistan on the show.

Even Lt-Col Rupert Thorneloe  1,000 men under his command, highest-ranking soldier to die in this war, a career that saw service in Northern Ireland, Bosnia and Iraq before Afghanistan hasn’t made it. But on Sunday evening, another former soldier was the lead obituary: Robert S. McNamara, defence secretary under Kennedy and Johnson, best known as ‘architect of the Vietnam war’.

With his slicked-down hair, steel-rimmed glasses and formidable intellect, McNamara is fixed in the minds of the gene-ration who lived through a futile war in which 58,000 Americans and between two to three million Vietnamese died. Nothing quite prepared me for the genial recollections in Last Word. Ted Sorenson described him as  ‘a thoughtful, forceful, articulate and compassionate friend’. Henry Kissinger insisted that he was ‘the executor, not the architect of the Vietnam war’. But the most compelling was Errol Morris, whose film The Fog of War received an Oscar for best documentary.

For two hours, the then 85-year-old McNamara was interviewed about his life and the conflict that, by 1964, had come to be known as ‘McNamara’s War’. Asked if the film was McNamara’s mea culpa, the film-maker replied: ‘No. How do you apologise for history?’

The film’s title refers to the uncertainty that hovers over the battlefield during fighting. The format is ‘R. S. McNamara’s 11 life lessons’, inspired by the former Secretary of Defense’s list from In Retrospect: The Tragedy and Lessons of Vietnam, published in 1995. Lessons that now seem so obvious: failure to understand the enemy, failure to understand the limits of high-tech weapons, failure to tell the truth to the American people the dangers to our country were exaggerated. Failure to recognise that we don’t have a God-given right to shape every nation in our image.

Lulled by the hum of combines, I could forget that this patch of Suffolk is the staging post for war: RAF Honington is three miles from here; Lakenheath and Mildenhall, the two largest US bases in Europe, less that 30 minutes away. By 1966, McNamara knew ‘the war in Vietnam was unwinnable’, but he couldn’t persuade the politicians for whom the pretence of future benefits appears better than admitting loss. Because lives have been lost, no one wants to write off sunken costs.

In 1967, McNamara was fired by President Johnson. Another 42,000 American soldiers would die in the seven years that followed. McNamara is described as wandering around Washington later in life, ‘a haunted man’. As I go out to check on the harvest, I wonder who will be the haunted men if we stay in Afghanistan; who, in a quiet and prosperous future, will be unable to apologise for history.

In the heat and dust of the grain store, I remember McNamara’s final two lessons of Vietnam. We failed to recognise that in international affairs there may be problems for which there are no solutions. That, at times, we may have to live with an imperfect, untidy world.