The Queen Mother was the illegitimate daughter of a French cook, and Queen Elizabeth II was conceived by artificial insemination, according to a shocking new book.

Aristocratic author Lady Colin Campbell insists that the derogatory nickname 'Cookie' was given to the Queen Mother by the Duke and Duchess of Windsor, a reference to the supposed working class status of the Queen’s mum’s “mum”.

Speaking at a press conference on Wednesday before the publication of her new tome, Campbell said she intends to lift the lid on royal rumours that have never before been aired. “It is time the truth is known, I am eager to have it on record before everyone dies," she said.

Lady Colin Campbell: "More than a darling adorable old granny"

The Queen Mother, born the Honourable Elizabeth Angela Marguerite Bowes Lyon, has the same middle name as the French cook Marguerite Rodiere, "because she gave birth to her", said Campbell.

PICTURES: Scroll down for images of Elizabeth Bowes Lyon

Despite that, she insists the mystery of the Queen Mother's birth should not influence debate about her suitability as a member of the royal family, saying she finds such opinions “gross snobbishness”.

"So what if [Cecilia Glamis] wasn't her birth mother?" she said, calling any other attitude to the revelation “odious”.

Lady Campbell, who was once married to the Duke of Argyll, claims that her connections to the royal family, both by blood and by marriage, have given her unprecedented access to inside sources for her latest work.

Her 1992 biography, Diana In Private, was the first book that exposed the calamitous marriage between Prince Charles and Diana, and was a Sunday Times and New York Times bestseller.

The book is out in the UK on 24 April

However her recent effort The Untold Life Of Queen Elizabeth, The Queen Mother, is likely to upset the royal family, casting a shadow over Queen Elizabeth II as she celebrates her diamond jubilee.

The book publishes “personal details” about the life of the current monarch’s mother especially her sexual mores.

"It was well known in royal and aristocratic circles for years, that Elizabeth [the Queen Mother], how shall I put this delicately, preferred not to partake of certain aspects of married life, and so Queen Elizabeth II had to be conceived by artificial insemination" said the author.

OPINION: Scroll down to leave your comments about the book

The publication also "lifts the lid" on the Queen Mother's supposed political machinations, and her role in the abdication of the Prince Edward, the former King Edward VIII, and later Duke of Windsor.

In the book, Lady Colin claims that the Queen Mother's "cronies" were planting stories in the American and British press "for years" to make sure that Elizabeth would become Queen, adding that the late Queen mother and her husband were suggesting to the press that the Duke of Windsor did not want to be king, which was "absolutely not true".

"It’s true that her cronies shoved him [Prince Edward] off the throne, the question is only to what extent she [the Queen Mother] did it herself", declared Campbell, arguing that the information was suppressed as the British nation "hasn't wanted to see the reality”.

"I think the blue rinse brigade will be absolutely horrified,” she said. “The public has only known the Queen Mother as a fantasy figure, a 'marshmallow made of steel'."

"She was a lot more than a darling adorable old granny."

Campbell also made reference to the Queen Mother's colder side, recalling her time as part of Princess Margaret's set in the 1970's.

"Margaret’s friends were horrified by the way her mother treated her, and I would shudder to treat my children with the lack of humanity with which Elizabeth treated her daughter," she told the assembled press.

According to the author, the late royal played a key role in Britain's declaration of war against Germany, noting, "Hitler loathed the Queen Mother".

"I believe in upsetting people when I write books," she said defiantly towards the end of the briefing.

"The truth will upset people, but they won’t be upset in six months. If they remain upset after that, well then they deserve to be."

Enjoy a gallery of Elizabeth Bowes-Lyons:

• Miss H G Hall's study of the Duchess of York aged seven.

• Lady Elizabeth Bowes-Lyon (later Queen Elizabeth, the Queen Mother), writing in the year before her 1923 marriage to the Duke of York (later King George VI).

• L-R: The Duke of York Prince Albert (later George VI) and his fiancee Lady Elizabeth Bowes-Lyon (later the Queen Mother), with her parents the Earl and Countess of Strathmore at Glamis, Scotland.

• Lady Elizabeth Bowes-Lyon (later the Queen Mother) leaving her home in Bruton Street, London, on her way to Westminster Abbey for her wedding to the Duke of York (later King George VI).

• Lady Elizabeth Bowes-Lyon (later the Queen Mother) leaving her home in Bruton Street, London, on her way to Westminster Abbey for her wedding to the Duke of York (later King George VI).

• Lady Elizabeth Bowes-Lyon (later Queen Elizabeth, the Queen Mother) leaving her Bruton Street home, London, before marrying the Duke of York (later King George VI) at Westminster Abbey.

• Lady Elizabeth Bowes-Lyon (later to be Queen Elizabeth, the Queen Mother) and Prince Albert, Duke of York (later to be King George VI) on the balcony of Buckingham Palace after their wedding ceremony at Westminster Abbey, London.

• Elizabeth Bowes Lyon (Queen Mother) after her wedding to the Duke of York (King George VI). With them are their parents, King George V and Queen Mary (right), and Claude Bowes-Lyon, 14th Earl of Strathmore and Kinghorne, and his wife Cecilia Bowes-Lyon, Countess of Strathmore and Kinghorne.

• The Duke of York (later King George VI) with Lady Elizabeth Bowes-Lyon (later Queen Elizabeth, the Queen Mother), posing for their official engagement photograph.

• The Duke of York (right) and his bride-to-be, Lady Elizabeth Bowes-Lyon, pass through cheering ranks of girls at the biscuit factory that is producing the Royal Wedding Cake.

• Lady Elizabeth Bowes Lyon in 1921, later Queen Elizabeth and the Queen Mother.

• The Queen, The Queen Mother, is seen at the Parliamentary Buildings Ottawa (Canada) signing the speakers books for the speaker of the Senate The Hon Ishart Robertson (left) and the speaker of the house the Hon L Rene Beaudoin 17th November 1954

• The Duke and Duchess of York leaving Buckingham Palace for their honeymoon, part of which is to be spent at Polesden Lacey, Surrey.

• The Duke of York (later King George VI) with Lady Elizabeth Bowes-Lyon (later Queen Elizabeth, the Queen Mother), posing for their official engagement photograph.

• A portrait of Elizabeth Bowes Lyon, the fiancee of Prince Albert, the Duke of York. She later became Queen Elizabeth when the Duke of York became King George VI in 1936, on the abdication of his older brother, Edward VIII.

• Lady Elizabeth Bowes-Lyon receiving a wedding gift made by a crippled boy at Alton cripples hospital and college. Sir William Treloar and his daughter and the boy who made the bag, George Perkins are also shown in the picture. Lady Bowes-Lyon married the Duke of York (future King George VI) in 1923.

• Today is St Patrick's Day, and The Queen Mother went to Victoria Barracks at Windsor to present the officers and men of the Irish Guards - nicknamed 'the Micks' - with shamrock during their traditional St Patrick's Day parade.