King George VI

Second son of King George V Took the throne in 1936 after his brother, Edward, abdicated Married Lady Elizabeth Angela Marguerite Bowes-Lyon Had two children: Elizabeth and Margaret Died at 56, in 1952

Literally overnight the power and responsibility for decision-making had unexpectedly left one Queen Elizabeth and devolved to another.

This led to a period of painful readjustment in the relationship between the Queen Mother and the new Queen Elizabeth II, one that probably neither would care to dwell upon half a century later.

One of the reasons that the 1977 Silver Jubilee celebrations and this year's Golden successor are taking place in June rather than at the actual date of the accession on Wednesday is to spare the Queen Mother's feelings.

The sensitivities surrounding her in her long widowhood became apparent the moment the king died at Sandringham on the morning of 6 February 1952.

On honeymoon: George VI and Queen Elizabeth were married for 29 years

The total reversal in their situations between the two queens at the time of the King's death posed significant emotional and psychological problems for both women, which they managed to overcome through good humour, common sense, genuine love and, of course, the lack of any realistic alternative.

Aged 25, the Queen was too old to require a regency, so there was absolutely no formal, constitutional role that the Queen Mother could adopt as her own. She had to create her new life, and at first it was not easy.

The first months were the worst.

"The Queen Mother minded so much she became unapproachable," recalled the daughter of one of her attendants, "and she also resented and was horribly jealous of her daughter becoming Queen so that at one blow not only did she lose the King but the whole of the happiest and gayest family life of anyone one knows all fell to pieces at the same time."

Mummy and Margaret have the biggest grief to bear for the future must seem very bleak, while I have a job and a family to think of

One of the Queen's letters

Although the new Queen made every effort not to upstage her mother in public, and went out of her way to ensure they entered public occasions together, the tremendous reversal in their roles could not be ignored, however sensitively and carefully the two women behaved.

When the Queen gave her mother the use of Sandringham, for example, she was highly sensitive to any suspicion that she could be thought to be usurping her mother's position as hostess.

"She would leap away from the teapot which she had been about to pour when she saw the Queen Mother approaching," a courtier remembers.

Under the same roof

The Queen's private secretary, Sir Alan Lascelles recalled the rather tense atmosphere at Windsor in the Easter holidays of 1952, soon after the king's death.

Proud parents with the newly-born Princess Elizabeth

It was the first time that the two queens were staying together under the same roof since the King's death and a certain amount of awkwardness developed over who should go into dinner first, "the Queen not wanting to go in front of her mother and the Queen Mother being used to go in first".

"The Queen Mother couldn't bear it - she was so young to be widowed and she minded the change in position although the Queen did everything to ease the change in position."

In the end, time and the inexorable facts of the situation - as well as the two women's common sense and devotion to one another - resolved the problems as the Queen Mother carved out for herself the unique role in British public life that she has so long enjoyed.

For a few months, however, there was much heartache. To read her private letters to friends about the death of the King - "He was my whole life"- is to appreciate how painful Wednesday will undoubtedly be for this centenarian royal phenomenon.

Andrew Roberts is author of A Royal History of England: the House of Windsor (Cassell 2000).