The vocabulary is one I’ve acquired: the cloakroom loo. When I came here as a bride, the throne like loo was in its own small room, but the basin, large enough to bath a baby, was in the passage, in the style of gun rooms and hunting lodges.

The taps were encrusted with the lime of ages and the porcelain was streaked by years of slow drips. On the marble shelf above sat a row of ivory brushes, engraved with initials and crests that had faded with use and time. I took against this sink. It was too masculine, too sordid-bristles stiff and brown with age and hair oil, linen towels limp and forlorn-and too public. I bought a shiny, characterless version and installed it inside the cloakroom.

Which is not a cloakroom, of course. No cloaks hang there, only pictures. On two walls hang photographs that span a century of the Harrow 1st XI, with names written in beautiful script, names that recur with each generation (Buxton, Barclay, Carlisle, McCorquodale). And on the third wall, another set of photographs, equally repetitive and masculine. It’s the Whips’ Office, in the late 1980s, a blur of men, distinguished mainly by varieties of height and hairlines. Seated in the middle of each photograph, looking immaculate, elegant and remarkably like Meryl Streep, is their leader, Margaret Thatcher.

Fished these photos out from the attic a few years ago because they seemed like a quirky souvenir of history, kitsch even: the female star in a chorus line of obedient suits. And then I never looked at the photographs again. The cloakroom still feels like the ‘gents’ to me, as masculine and impenetrable as the Whips’ Office, but I remembered the images last week as I watched The Iron Lady. I tried to persuade my husband to go with me. After all, he was one of the obedient suits, swept into Parliament in 1979 with a majority of 600 votes, but he refused. He hated the whole idea of a film portraying the Prime Minister as an old lady who has lost her mind.

‘A ruthless invasion of privacy, a lack of respect,’ he grumped. Sitting in the dark, however, I missed him. Throughout the film, I wanted to ask him questions. Did Mrs Thatcher ever wear a hat in the Commons? (No.) Was she in the Commons underground car park when Airey Neave’s car was blown up by the IRA? (No.) But The Iron Lady isn’t a documentary. It’s a drama and, at its best, it directs you towards the greater truth. It’s also been described as a brave and brilliant film about that most taboo subject, dementia.

The viewer travels down the road of history via the flashbacks and faded memories of the former Prime Minister. More compelling, however, will be the realisation to anyone who lived through the Thatcher years that we all suffer from a kind of dementia. We’ve forgotten the sheer horror of the years when the IRA was as brutal as the sectarian bombers in Iraq and Afghanistan are today. We’ve forgotten Airey Neave and Ian Gow, forgotten how close the IRA came to killing the Prime Minister in Brighton. Who, indeed, can remember the names of anyone killed in that bombing?
We’ve also forgotten how divided the country was during those years. In the fog of history, Mrs Thatcher is remembered as a divisive figure, but she came to power in a divided country.

Did the miners’ strike, the doomed Poll Tax, deepen those divisions or simply make them more obvious? Although Miss Streep is mesmerising, the great strength of The Iron Lady isn’t in the acting. The real achievement is how the heroine’s flashbacks trigger our own memories, both triumphant and tragic. At a time when the leaders in Westminster are (again) all sons of privilege, it’s useful to remember the leader who pene-trated that masculine and class enclave. Margaret Thatcher is a part of our lives and time. She was flawed and she was remarkable. It’s worth remembering.

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