Although it does little to dilute the attention-deficit disorder aggravated by too many plotlines and too many advert breaks, I concocted a way to watch Downton Abbey without going nuts. The instant a scene ended, I pressed the ‘mute’ button, and opened a book. It didn’t always work. Sometimes, I added logs to the fire, filled my wine glass or let the dog out. Still, I’d made a vow.

After the first episode, I went to a sacred shelf on my husband’s side of the library, the John Buchan shelf, and took out a slender volume called These For Remembrance: Memoirs of 6 Friends Killed in the Great War. For years, I’ve shown bemused tolerance toward my husband’s revered writer.

Convinced that The Thirty-Nine Steps and Greenmantle were the English versions of the ‘Hardy Boys’ books, even when I saw Buchan’s autobiography Memory Hold-the-Door in the Kennedy Library, on the shelf of JFK’s favourite books, I gave the writer a miss. But after war was declared in Downton Abbey, I remembered These For Remembrance.

In late 1918, when the Armistice ended what was then the greatest war in history, Buchan relinquished his post as Director of Intelligence and, exhausted and ill, returned to his wife and children. ‘The war left me with an intense craving for country life,’ he wrote and his first task was to put down roots in the Oxfordshire countryside. Then, still haunted by his memories of war, he began to write about the lives of friends whose ‘riches of heart and mind, abounding zest for life, faithfulness and courage’ had been the heart of his happier life, friends who had not returned from ‘this bloody and disgusting war’.

The plan was to ration myself to one ‘friend’ per Downton episode. Except for Raymond Asquith, ‘the cleverest man of his generation’, the names-Tommy Nelson, Bron Lucas, Cecil Rawling, Basil Blackwood, Jack Wortley meant nothing to me. But as the Sunday nights of autumn went by, their lives began to provide something that was missing in the melodramatic and unrealistic scenes at Downton. None of the men had achieved great distinction-they had nursed their promise, but not yet fulfilled it-but they were real men, believable men.

And the problem with Downton revisited is that although seductive, even addictive, it wasn’t believable. Even the prolonged torture of the First World War (filmed in Suffolk,in a permament, purpose-built Western Front trench) whizzed by.

In the world of film, timing is everything. No one knows that better than Julian Fellowes, whose timing in Gosford Park is as flawless as a Mozart quartet. Timing is essential for subtlety and plausibility (although a Turkish diplomat dying immediately after love-making is not great timing). It can’t be easy writing scenes between award ceremonies and trips to Buckingham Palace, but even a writer as gifted as Lord Fellowes needs time to think and time to delete.

With more time, Patrick the heir, drowned on the Titanic only to mysteriously surface after six years, would have found himself on the cutting-room floor. With more time, the bloodless Sir Richard Carlisle (no relation) would have at least one redeeming quality, if only to make Lady Mary more convincing. As it is, above stairs, only the beautiful, tolerant and humane Lady Grantham, Cora, whose American fortune has kept the Downton show on the road, and Violet, the languid, wisecracking Dowager Countess, merit my uncritical devotion.

But I’m glad I’ve discovered Buchan, the writer who was far from convinced that the First World War had made the world safe for democracy. More than ever, he sensed barbarians lurking on the frontier, ‘with dangerous appeal to the debt-ridden, declassed, over-taxed, dispirited, degenerate’. I’m tempted to say that it sounds hauntingly familiar, but the Dowager Countess’s voice rings in my ear: ‘Don’t be defeatist, dear. It’s very middle class.’