Who is Carol Thatcher – and how realistic is The Crown's portrayal of her relationship with her mother?

So what do we know about the real history behind The Crown, and the real Carol Thatcher? Here are all the big questions answered.

Who is Carol Thatcher?

Carol Thatcher is the daughter of Denis and Margaret Thatcher. She and her twin brother Mark were born in 1953, and when they were six years old their mother was elected a Conservative MP. By the time Margaret Thatcher became the country's first female Prime Minister in 1979, her twins were in their mid-twenties and had already begun their adult lives.

After gaining a law degree from University College London, Carol trained as a solicitor but then moved to Australia in 1977 and started work as a journalist at the Sydney Morning Herald. After a couple of years on the newspaper, she made her debut as a TV reporter.

Carol later returned to the UK, working for LBC and the BBC and even writing travel articles for The Daily Telegraph. But her career was, of course, affected by her being the Prime Minister's child: as her editor at the Telegraph, Bill Deedes, said in 2005, "She was cut off by quite a bit of the press who wouldn't run anything with Carol Thatcher's byline."

The BBC once summarised how Carol made it as a journalist despite that tricky position: "By refusing to be drawn into any political arguments, she avoided fallout from her mother's many critics. Carol has become a stalwart of what she has called 'airline literature', the articles you find in in-flight magazines. This has meant lots of travelling on her own. She once cycled 100kms a day across Russia."

Perhaps sensibly, Carol soon turned her journalistic skills to an area where she had exclusive access: she wrote about her own parents. In 1983, she travelled with her mum around the country and published her first book, 'Diary of an Election: with Margaret Thatcher on the Campaign Trail'.

And after Margaret Thatcher had left office, Carol focused on telling the story of her father – writing a 1996 biography of Denis Thatcher called 'Below the Parapet', and producing a 2003 documentary about him called 'Married to Maggie' which featured the only public interview he ever gave.

Did Carol resent that her brother Mark was the favourite?

One episode of The Crown season four, "Favourites", tells the story of how Mark Thatcher went missing in 1982 during a motor rally. It also uses that incident to explore Margaret Thatcher's relationship with her son and daughter, and Carol's resentment about Mark being clearly the favourite child.

And yes, this is based on genuine accounts of those relationships.

Carol herself has had something to say about it, particularly in her 1996 biography of her father and the interviews she gave to promote the book. "Unloved is not the right word... but I never felt I made the grade... I always felt I came second out of two," she said. She also once wrote: "He was always more glamorous. In comparison, I was one-dimensional and dull."

Biographer John Campbell writes that, despite Thatcher's "paeans to the centrality of family life", the family was not very close: "It never had been when the children were young, when she [Thatcher] was making her career and Denis was away travelling for long periods for his work. Carol's account of their childhood in her biography of Denis portrays her mother as a very remote and preoccupied parent."

He adds: "In a curious reflection of her essentially masculine outlook, she was uncritically devoted to Mark while continuing to undervalue Carol." As for Mark, "she has steadfastly refused to hear any criticism of him."

Mark moved to Texas in 1984, married an oil heiress, and started a family (while continuing to get richer and richer). But he rang his mother every week – and those calls were very important to her.

Thatcher's friend Woodrow Wyatt said in 1987: "A different note comes into her voice when she speaks about Mark. She obviously dotes on him. I think he is a pretty good washout. He gives a lot of trouble to his mother. She puts up with it as mothers do with their favourite son or child."

In 1996, Carol remarked: "Mark is married to a beautiful girl, has two fabulous children and various mansions scattered around the world. I'm an ancient spinster of no fixed abode living in a rented holiday flat in a ski resort. I still don't measure up awfully well on the Richter scale."

What was Margaret Thatcher's relationship with Carol?

It does seem to have been quite tricky. Margaret Thatcher herself didn't really talk about it, but Carol has been more open in sharing her experiences. She's talked about how for 12 years she communicated with her mother via her secretaries, and about her mother's remoteness when she was a child.

But she also clearly felt a duty to her mother and to her family name – especially if she could bring more credit than her twin brother. In an interview in The Lady in 1996, Carol said of Mark: "In some ways he has behaved appallingly. I tried to behave in a vaguely respectable fashion because Mark got such awful publicity... I didn't want everyone saying: 'Mrs Thatcher must be awful; both her children are off the rails'."

While Margaret was clearly closest to her son Mark, there was a father-daughter bond between Carol and Denis which seems to have become closer over the years. He was the one whose life she chose to write about, although Margaret Thatcher never actually read Below the Parapet. (Or at least never admitted to it.)

At one point in the early 2000s, Thatcher complained about not seeing her children because they lived abroad (in South Africa and in Switzerland); Carol responded, "A mother cannot reasonably expect her grown-up children to boomerang back, gushing cosiness and make up for lost time. Absentee Mum, then Gran in overdrive is not an equation that balances."

But on the death of her mother in 2013, Carol told press: "I would just like to say that I feel like anyone else who has just lost a second parent. It's a deeply sad and rather thought-provoking moment in life... I know this is going to be a tough and tearful week, even for the daughter of the Iron Lady."

Did Carol live at 10 Downing Street?

Rarely! For the first few years she was in Australia (popping back just for the 1979 election), and later she lived elsewhere. But just as we see in The Crown, she was on hand in 1982-3 to gather material for her book and also to write a daily column about the election campaign.

Campbell writes: "They [Mark and Carol] both dripped in and out of Downing Street from time to time, but Carol had the good sense to take herself out of the way and made her own career in Australia for much of the time, working as a journalist, though she came back in 1983 to cover her mother's re-election for the Daily Mail."

In the run-up to the 1982 Falklands invasion Sir Frank Cooper (Permanent Secretary at the Ministry of Defence) recalls Carol fetching "a bit of ham and salad" from the fridge when he visited the flat above Number 10 for Sunday lunch, and Margaret Thatcher's biographer John Campbell talks of how Carol "made herself useful as a general dogsbody" during the 1983 campaign.

Where is Carol Thatcher now?

In 2005, Carol Thatcher competed in the reality show I'm a Celebrity... Get Me Out of Here! - and won the show, as well as plenty of admirers. Her mother was still alive at the time, but Carol didn't pre-warn her about the reality TV stint: "She'll probably be very critical. It's not her sort of show, so I might just tell her I've done it when I get back."

She continued her career as a freelance journalist and as an author, having written other books including a biography of tennis-playing couple John Lloyd and Chris Evert. She also continued to live in Switzerland with her ski instructor partner Marco Grass. In 2006 Carol described herself as "a complete and utter globe-trotting nut".

In 2009, Carol Thatcher again hit the headlines after referring to a professional tennis player as a "g*****g" in a private conversation in the BBC green room after recording an episode of The One Show. She was discussing the Australian Open with Adrian Chiles and comedian Jo Brand.

Carol's spokeswoman said the comment was an "off-the-cuff remark made in jest". After the incident BBC spokesman said: "We will no longer be working with Carol Thatcher on The One Show."

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Since then, Carol has not appeared on TV except in a documentary about her mother (and in news broadcasts after her Margaret Thatcher's death in 2013).

But in 2015, she did decide to auction off hundreds of her late mother's belongings in an auction at Christie's, leading to reports in The Mail on Sunday of "a bitter family feud which has left her two children at loggerheads" as Mark was opposed to the sale.

At the time of The Crown season four's release, Carol Thatcher is 67.

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