Meryl Streep’s gripping portrayal of Margaret Thatcher did not do full justice to her remarkable ability to make sure that not only male politicians – but also radio and television interviewers – were kept firmly in their place. Her mere presence was enough to strike fear into the hearts of eminent broadcasters and producers.

Unlike so many of her political opponents she treated each interview as a battle for supremacy and from the moment she entered a studio and sat down in front of the microphone, she took no prisoners.

Streep’s portrayal of Thatcher in The Iron Lady captured the all-conquering nature of her Premiership at the height of her power.  But some of the early scenes – as she fought to get elected as MP at Dartford and then succeeded at Finchley – did give a hint of vulnerability.

I remember my first interview with her in early 1975 – as she campaigned for the Conservative Party leadership – because there was a degree of informality which was not to be repeated. Indeed on seeing The Iron Lady I can hardly believe it myself.

Margaret Thatcher’s challenge for the Tory leadership was a terrible blow to the former Prime Minister Edward Heath. She defeated Heath on the first round and was then declared leader on 11 February, 1975 after winning a run-off against William Whitelaw.

One of her leadership campaign events was a visit to a Young Conservatives’ conference in Eastbourne and my task a political correspondent was to secure an interview for BBC Radio 4.  At the time she was determined to woo the news media and in a rare moment of intimacy I was allowed to sit next to her on a settee in the lounge of the conference hotel.  With my Uher tape on me knee I proceeded to ask what were probably some pretty run-of-the-mill questions about her leadership campaign.

On being elected leader and with the guidance of the political strategist Gordon Reece – who went on to overhaul her presentation during the 1979 general election – she became far more wary.  She kept her distance from interviewers and never, in my experience, engaged in the gossipy exchanges with broadcasters which so many politicians enjoy; sitting next to her at a conference hotel would have been unthinkable.

The informality of my encounter at Eastbourne was all the more surprising because, unlike her successor John Major, she had already been bloodied in her encounters with journalists during her stint as Secretary of State for Education in the Heath government.

At no point in Major’s short ministerial career had he been subjected to the kind of hatred and vilification heaped on Thatcher when she withdrew free school milk for seven to eleven year olds and was dubbed “Margaret Thatcher, Milk Snatcher” – an episode ignored by the producers of The Iron Lady.

The characteristic which marked Thatcher out was her steely self discipline. She worked on the assumption that an interview had started the moment she walked through the studio door and this was not the occasion for small talk on similar asides.

Her reputation was legendary and the only pleasantries she allowed herself were about trivialities which still had the power to intimidate producers and technicians.  Her insistence on British rather than French bottled water became a favourite opening gambit in her warm-up routine.

I can still visualise the look of sheer panic on one producer’s face when he realised that the only water available was Perrier. Why he demanded, was there no Buxton water, the only safe alternative?

Jon Snow reflected on his drubbing at the hands of Thatcher in an interview for the London Evening Standard (13.1.2012). He interviewed her on at least twenty occasions and considered “everyone was a disaster.”

Snow said the Prime Minister would often say “Oh Jon, how perfectly lovely to see you” and then give him the run around. “As soon as the camera started rolling the dynamic changed and her first answer to any question would be: ‘What a perfectly stupid question!’ It always went the same way.”

Mrs Thatcher had not only a commanding presence but also an ability to think ahead as to what the pictures might look like. My suspicion that she could perform for the cameras and almost simultaneously look down the viewfinder as well was confirmed for me yet again when waiting for her comment on the Clapham rail disaster of December 1988.

Reporters and television crews were assembled in a room containing the No.10 Christmas tree. We were told that first of all officers of the Grantham Rotary Club intended making a presentation to the Prime Minister. She would speak to us about the rail crash afterwards. 

Mrs Thatcher posed with the Rotarians in front of the tree while the official photograph was taken. Once the ceremony had finished she turned towards the television cameras and microphones, and as she did so she began walking away from the tree towards a fireplace on the other side of the room, saying it would be inappropriate at a time of grief to be filmed in a seasonal setting.

She seemed to know instinctively that a neutral backing would be more in keeping with the sombre statement she was about to make. We had been caught by surprise at her sudden change of position; she had begun moving across the room before a press officer could possibly have intervened or prompted her to get away from the tree.

Her knack of being able to visualise the effect she might be creating stood her in good stead at times of crisis.  In her memoirs The Downing Street Years, Lady Thatcher described how she maintained a “mask of composure” while she sat on the front bench listening to the resignation speech by Sir Geoffrey Howe which triggered her downfall.  Her emotions were in turmoil but she realised that she herself was as much the focus of attention as was Sir Geoffrey.

The proceedings were being televised, and up above her were the reporters in the press gallery. When interviewed for the television series which accompanied publication of her memoirs, Lady Thatcher described the fateful moment: “I knew the press were watching me. I had to keep my face calm.”

Illustrations: Mail on Sunday, 27 November, 2011; Daily Mail, 12 January, 2012.