It was 100 years ago today that a by-election in the constituency of Plymouth Sutton saw the election of the first woman to take her seat in Parliament.

Nancy Astor made the historic breakthrough by winning the seat vacated by her husband, Waldorf Astor, when he succeeded his father to become the 2nd Viscount Astor.

There are celebrations to mark her smashing the glass ceiling, but as we shall see, the pioneer somewhat blotted her copybook in later life.

WHY WAS SHE THE FIRST?

The Representation of the People Act in 1918 had given the vote to women of age 30 and over, but the courts - yes, they got involved in political matters even back then - decided the new law did not allow women to stand for Parliament.

With the suffragette movement crying ‘foul’, the coalition Government of David Lloyd George swiftly brought in a new law, the Parliament (Qualification of Women Act) 1918. It remains the shortest law on the statute book at 27 words: “A woman shall not be disqualified by sex or marriage for being elected to or sitting or voting as a Member of the Commons House of Parliament”.

The first woman elected to the House of Commons was Countess Constance Markievicz who won the Dublin St Patrick’s constituency in the general election of December, 1918, but with other Sinn Fein MPS she refused to take her seat.

That left the way open for Nancy Astor to become the first woman to sit in either House in Parliament - women were banned from the House of Lords until the Life Peerages Act of 1958.

HOW DID SHE WIN?

The UK Government at the time was a coalition of Lloyd George’s ‘Coalition Liberals’, as opposed to the Liberals, and the Conservatives led by Andrew Bonar Law, MP for Glasgow Central.

When her father-in-law died in October, 1918, Nancy and the new Viscount Astor came up with a plan to have her stand as his replacement.

It was Nancy who had encouraged Waldorf Astor to enter politics in the first place, and he was a public figure as owner of The Observer newspaper.

In 1919, the suffragettes had changed the status of women and the wartime work of millions of women had encouraged a change in society’s attitude to women attempting to enter male dominated parts of life such as politics.

Standing as a Unionist, on November 28, 1919, Nancy wiped the floor with the opposition, winning by a landslide despite the attitude of some electors to her pro-temperance views and the fact that she was both American and divorced. Her witty answers to hecklers at hustings were well reported and her victory was no surprise.

On December 1, after a triumphant train journey to London where she was met by a crowd of women who duly escorted her to Parliament, Nancy Astor took her seat in the House of Commons.

Dr Jacqui Turner, historical advisor from the University of Reading who is leading the Astor 100 programme of activities to mark the centenary, said: “The election of Nancy Astor changed British democracy forever. For the first time, a woman was able to directly influence the parliamentary debate and the writing of the laws of her own land. A responsibility she willingly shouldered for all women.”

WHO WAS SHE ORIGINALLY?

Astor was born Nancy Witcher Langhorne in Danville, Virginia, on May 19, 1879. At one time the family were quite poor, but her father built up a business that made them relatively wealthy.

She had three brothers and four sisters who all survived childhood, and the five girls were noted for their good looks. After attending finishing school in New York, at 18 Nancy married a society figure, Robert Gould Shaw II, but almost left him on their honeymoon as he was an abusive drunk.

They stayed together long enough for Nancy to have a son, imaginatively named Robert Gould Shaw III, before she divorced her husband in 1903. She toured Britain shortly afterwards and decided to stay, meeting and marrying Walford Astor.

They became society hosts and moved in political circles, with Nancy agreeing with, though not actively participating in, the suffragette movement.

HOW DID HER CAREER GO?

As Britain’s first active woman MP, she advocated greater rights for women and also campaigned for prison reform and age limits on alcohol sale.

She never achieved high office but became famous for her wit in dealing with men in the Commons, though Boris Johnson, no less, has cast doubt on whether she made all the witticisms she directed at his hero Winston Churchill.

Churchill apparently told her that having a woman in Parliament was like having one intrude on him in the bathroom, to which Astor retorted, “Sir, you are not handsome enough to have such fears”. Churchill got his own back. She apparently told him that if she was his wife she would poison his tea to which he replied “if you were my wife I’d drink it".

She definitely did say: “I married beneath me. All women do.”

Her other aphorisms include “the main dangers in this life are the people who want to change everything... or nothing,” and “pioneers may be picturesque figures, but they are often rather lonely ones.”

HOW DID SHE UPSET PEOPLE?

Nancy Astor was at various times quite anti-semitic, racist and anti-Catholic. She denied that her ‘Cliveden Set’ named after her country home was quasi-fascist in its collective views, but her friend Lord Lothian was one of the leading pro-appeasement figures in the 1930s.

She lived until 1964, dying at the age of 84. A statue of her will be unveiled on Plymouth Hoe later today by former prime minister Theresa May.