Margaret Thatcher: my part in her downfall.

It was the 1987 general election campaign. I'd recently been made the BBC's Scottish political correspondent and I was furious that Prime Minister Margaret Thatcher had refused to give me an interview. So, when she arrived for a “whistle stop” press conference at Glasgow Airport, I was determined to get something out of her.

After her scripted remarks, I started hurling questions at her without waiting to be called. “Whatever happened to Tory promises on a better devolution, Mrs Thatcher?...What have you to the hundreds of thousands of Scots thrown out of work?...Do you not accept that your poll tax is destroying the TorIes as a political force in Scotland? ”. She answered my early questions, but at this she halted and said in those inimitable tones: “That's quite enough from you, young man. Now, does anyone else here want to ask the poll tax question?”. There was silence from rest of the hack pack who were clearly enjoying seeing the press conference turned into a car crash. Grudgingly she continued, and though my editor had to cut the bits and pieces together afterwards, we got an interview of sorts.

I was quite out of order, of course, and I rather cringe at the thought of it. As I was leaving she looked directly at me with that deadly smile and a shake of the head which said: “Ok – but don't think you're so clever.” I only interviewed her properly once after that and it was an uncomfortable affair. Almost as uncomfortable as seeing her again, ten feet high, on the cinema screen meticulously recreated by Meryl Streep in The Iron Lady. It was like being back a that press conference.

I realised that no actress has really captured the essence of Margaret Thatcher before Streep. Her Spitting Image puppet was much too crude and none of the distinguished actresses who've played her down the years – Lindsay Duncan, Patricia Hodge, Maureen Lipmann – have come close. Janet Brown's comic impersonation in the 80's was nearly there, but with Thatcher, nearly isn't enough.      Meryl Streep's portrayal  is terrifyingly accurate: the coquettish demeanour, the hectoring tones, the evangelical zeal that turned every political speech into a pulpit sermon on the philosophy of individualism and enterprise. All the more astonishing since for most of the film, Streep plays Thatcher, not as the Iron Lady, but as an octogenarian suffering dementia and wrestling with delusions that her husband, Denis, is still alive..

Opinions on this film have been almost as divided and divisive as the lady herself. Many have loathed it. The BBC's Mark Kermode said it contained “all of the political clout that you would expect from a film directed by the maker of Mamma Mia”. So, I arrived at the cinema at fully expecting to leave before the end. But I was riveted to my seat throughout. It really is mesmerising, and emotionally engaging in a way I have rarely experienced, certainly in any Hollywood biopic. This is no hagiography, and nor is it contrived, sentimental or artificial. It is quite simply the real thing.

However, Thatcher's political story, as told through a series of flashbacks, is less compelling and very much the gospel as told by St Margaret. Though here too, as the real Iron Lady, Streep performs brilliantly. Whether it is haranguing Labour at the Dispatch Box (mind you, she would never have been allowed to wear a hat in the Commons); humiliating her Foreign Secretary, Geoffrey Howe, in cabinet or  recovering from the Brighton bombing in 1984, Streep is thoroughly convincing, even if the history isn't. They missed a trick, though, in not using her last outing at the Dispatch Box in 1990, the one when she declared: “I'm enjoying this!”.

Streep achieves this feat of characterisation by going hugely over the top, exaggerating every Thatcher mannerism. But it works – mainly because Thatcher really was a kind of self parody. I moved to Westminster in 1989, and I must have seen her at a hundred speeches and receptions where she was the centre of attention (was she ever anywhere else?). What always struck you first – after remembering how much smaller she is in real life – is that she was so obviously acting a part. Partly this was because she had been trained by an army of media advisers, spin doctors and speech writers. But mostly it was her. And her fall was her greatest performance of all. I was in the Members Lobby of the Commons on the morning she resigned in November 1990, and saw senior Tories literally in tears. It was like a Tory Evita. Putting the Mamma Mia director in charge wasn't so daft after all.

If I subscribed to the thesis of director of the Iron Lady, Phyllida Lloyd, that Margaret Thatcher was a proto-feminist icon, I would probably say Thatcher's theatricality was necessary because she had to reinvent herself to compete in a masculine world. There was no way that she would be taken seriously, so she created a kind of caricature of a political wife – making eggs for Denis's breakfast in the Number Ten kitchen, before going off to sink the Belgrano. Advising mothers on how to stockpile food, before taking on Arthur Scargill's miners. Her affected 'pawh pawh' delivery was like a Tory grandee sounding off after one too many brandies in his club, even as she looked and dressed like a suburban housewife of the 1950s. It was all artifice, and she knew it.

But she got away with it because of her magnetism. Recently, a scientific journal trying to explain the Higgs Boson invited readers to imagine Margaret Thatcher entering a room and becoming the focus of attention from everyone in it. I know exactly what that meant. Even though she was shoulder high, it was impossibly not to be drawn to her. I don't mean sexually, though a number of Tories, including the late diarist and roue Alan Clark, claimed to have been turned on by her. It was something to do with her resolute unwillingness to allow anyone else to distract one iota of attention.

The Iron Lady is a feminist take on a woman who was loathed by all the feminists I ever new. This is the film's major weakness. I didn't mind that her story is told through flashbacks as she copes with loneliness – a perfectly acceptable theatrical device. However, the relentless reminders about how she was a woman in a man's world begin to grate, and the suggestion that she was seen by any women as a feminist role model is quite wrong (even though in a real sense she was).  She would certainly have been horrified if anyone suggested that she supported “women's liberation”. Margaret Thatcher's morality was unshakably based on thoroughly conventional, middle class family values. The attempt to cast her as a feminist  rather diminishes her actual historical significance. Of course, Margaret Thatcher was a powerful woman in a male-dominated political culture, and she had to put up with a lot of chauvinism. But she was an awful lot more than that.

I speak as no starry eyed nostalgic when I say that Margaret Thatcher was Britain's most significant post war prime minister. Like many Scots, I rejected almost everything she stood for, but no other leader – MacMillan, Wilson, even Churchill as a peacetime PM – had such a dramatic impact on political culture, or on the lives of ordinary people. Particularly in Scotland where he economic policies destroyed an entire industrial way of life. She came to power after the so-called “Winter of Discontent” in 1979 and went on to wreck the working class as a political force by taking on the miners in 1984 in Britain's last great industrial struggle. The present financial crisis has its origins in the wave of deregulation she inspired in the City of London, called 'the Big Bang' in 1986. Her privatisation of state utilities began as a financial expedient, but turned into an economic policy pursued by conservative and socialist governments across the world. The sale of council houses for massive discounts was a masterstroke – the biggest political bribe in history. Even my auntie May bought her Glasgow council house, and she hated everything she stood for. When Thatcher came to power, home ownership in Scotland was lower than in Communist countries like Poland, now it is the same as in England. Thatcher ignited a real estate bubble that only finally burst in the last two years, leaving a generation of young families as mortgage slaves. But the massed ranks of Britain's wealthy have Mrs Thatcher to thank for the bonus culture and for cutting the upper income tax rate in half. Tony Blair reinvented Labour in her image.

But don't expect these issues to be raised or examined in this film. It isn't a documentary or a political statement. The flashbacks are formulaic and serve only to show her resolve in the face of the many men who opposed her and tried to limit her ambition.  Though, curiously, while it isn't a political film, this cinematic Thatcher may have a considerable political impact, if only because it is one of the most sensitive and truthful portrayals of old age in the history of cinema. Whatever you think of her policies, it's hard not to identify with this goddess in her twilight. The ageing political superstar is shown struggling to retain her dignity and humour even as she is patronised and infantilised by her minders. It shows growing old as a struggle, ever bit as demanding as leading a political party.

The last time I spoke to Margaret Thatcher face to face was after the unveiling of her official portrait in Westminster in 1992 two years after she'd lost power. She hated it, needless to say. But she wasn't going to say so with the artist Henry Mee standing next to her. I suggested that it looked a little severe and she replied: “When you have been Prime Minister for eleven years you are no pushover”. She certainly wasn't. Before Thatcher there was a rule that no image of a politician could be hung in the Palace of Westminster until ten years after their death. The rule was broken for her, and she's been hanging in the Commons for nearly two decades.

And now she has been immortalised before she has even died. This film is likely to be shown again and again, decade after decade, to mark every anniversary of the Iron Lady's life, and eventual death. It may even ignite public support for Lady Thatcher to receive a state funeral when she dies – the only politician since Churchill to be so honoured. Though I don't think many Scots will be turning out to cheer her funeral cortege.