Margaret Thatcher not only promoted the concept of family life throughout her political career, she was also someone for whom the family was an essential part of her own life.

She said many times that she could not have achieved what she did without the help and support of her husband Denis, 10 years her senior.

He was, she once said, "the golden thread running through my life" - the man "who has made everything possible".

Throughout their marriage - which lasted more than 50 years - there was never anything, publicly at any rate, to suggest that they enjoyed other than a loving and rewarding partnership.

But there were crises in her family life as well. Some months after the death of her husband, their son, Sir Mark, was charged in August 2004 with plotting a coup to overthrow the Government of oil-rich Equatorial Guinea - a charge which could, in its extreme, have led to the death penalty.

This deeply upset his mother whose health was fragile anyway. But to her intense relief, he entered a plea bargain and a guilty plea and was punished with a large fine and a suspended prison sentence.

Although she rarely showed emotion in public, behind closed doors she was known occasionally to weep at the end of tumultuous days, especially during the Falklands conflict.

Denis was always there to comfort her - and, out in the streets all over the world, to protect her from over-enthusiastic, and occasionally malign, people who turned out to see her.

But the family in which she grew up did not really conform to the norm. Her father, Councillor Alfred Roberts, a grocer in Grantham, was a toiling, God-fearing, church-going fellow who instilled in her the virtues of the work ethic - something she was to embrace wholeheartedly throughout her life.

He met his wife Beatrice Stephenson, a seamstress, at the local Wesley Methodist Chapel. She has been described as "plain as dry toast, with her hair drawn primly back in a bun".

Margaret's sister Muriel was born four years before her. Unlike her younger sister, Muriel was a quiet, withdrawn girl, without much ambition. Hardly surprisingly, the two girls were never close. Muriel married a farmer and subsequently Margaret barely ever mentioned her existence.

But Margaret doted on her father and seemed to have less and less to say to her mother as she grew up.

And although Margaret confessed once to liking housework, like her mother, the two never hit it off. She was once quoted as saying: "I loved my mother dearly, but after I was 15 we had nothing more to say to each other."

After her school and university days, Margaret Thatcher turned from science to politics. It was when she was fighting the Dartford constituency in 1950 - which she lost - that she met her husband.

He was the director of a paint firm and helped Margaret by driving her around. He proposed, she accepted, and they were married in the autumn of 1951. She was then 26.

In fact, Margaret was his second wife. He had married another Margaret in 1942. Four years later there was an amicable divorce.

Not only Margaret Thatcher herself, but many of her friends believe that she would never have made it to Downing Street without Denis in the background.

But his support was discreet. He never made statements to the press or went on television. Throughout, he was the ideal consort.

Sometimes, when he was chatting to reporters on foreign trips, he would describe her as "The Boss". But he was always loyal and affectionate.

And when defeat for her seemed inevitable in the 1990 Tory leadership contest, he told her, according to friends, "Darling, I don't want you to be humiliated" - and she bowed out.

A year after her wedding, Margaret became pregnant. And in the August of 1953, seven weeks early, she gave birth to twins Carol and Mark by Caesarean section.

It was in 1959 that she got into Parliament as MP for Finchley, the seat which she was to represent until she left the Commons more than 30 years later.

Her hands were full. A busy parliamentary life and two young children. The family used to go on holiday to the Isle of Wight. Mark has since said that they were not brought up strictly, but found that if they behaved reasonably well, then there was no trouble.

The twins were, and are, starkly different from each other. Mark, a serious individual, is a businessman - and a highly astute one at that - first and foremost, while Carol, a journalist, is more easy-going and sociable.

Whereas Mark appears to keep his thoughts to himself, Carol is far more outgoing, often joking, but affectionately, about her parents, whom she invariably in public describes by their first names.

It was when Mark was briefly lost in the Algerian desert during a motor rally that his mother's composure dropped in public. She was seen to shed a tear as she left a meeting.

One of the most poignant moments was when her grandchild, Mark's son Michael, was brought to her for the first time at 10 Downing Street. That was when she made the famous "We are a grandmother" remark.

But for all her political ferocity, there is no doubt that Margaret Thatcher doted on small children, whether in her own family or not. It was a trait in her character which only her closest friends were aware of.

But it was Denis who summed up his ideal as a family man. "My idea of heaven," he told friends, "is sitting in my garden on a warm June night with a bottle of bubbly and my wife in a reasonably calm frame of mind."

Margaret Thatcher would have gone along with that.

But one of the saddest spectacles of her life was to see her, frail, confused and woebegone, at Denis's funeral in July 2003.

Later, she was to suffer another personal trauma, when Sir Mark was charged in South Africa in connection with an alleged coup to overthrow the Government of Equatorial Guinea.

The news broke when Lady Thatcher was on holiday in the United States. She doted on her son and the charge plainly devastated her.

However, after weeks under house arrest in Capetown, where he lived, Mark in January 2005, pleaded guilty to unwittingly helping to finance the foiled coup plot. He accepted a three million rand fine and a suspended jail sentence.

Judge Abe Motala told him to pay the fine as part of the plea deal, but if he failed to do so by January 17 that year, he faced a five-year prison sentence with a further four years suspended for five years.

Meanwhile his wife Diane and their two children had returned to Dallas, and he planned to rejoin them immediately. However his conviction led to problems about his entry into the United States and instead he returned to London to stay with his mother.

For her it was a massive relief that her son avoided a long prison sentence and also, more traumatically, avoided what could have resulted in a fatal extradition to Equatorial Guinea.

A few years later, Carol described in a book her mother's health problems.