Wide of the Markievicz
Health Secretary Matt Hancock got some basic history wrong this morning:
Nancy Astor was not the first female MP; she was the first woman to take her seat in Parliament.
The actual first woman to be elected as an MP was Constance Markievicz, an Irish Republican (and socialist, suffragette and revolutionary) who was elected as a Sinn Féin MP for the seat of Dublin St Patrick's in December 1918, just under a year before Astor won her seat. (This was before Ireland gained independence from the UK, which was kind of the point of Markievicz’s candidacy in the first place.)
As is still the case with Sinn Féin MPs, Markievicz did not take her seat in the Commons; she did not recognise the legitimacy of the Westminster parliament and refused to take the oath. Also, she was in jail in Holloway Prison at the time. But she was still the first female MP.
Nancy Astor was elected for the Conservatives to the constituency of Plymouth Sutton in a by-election in November 1919–the seat had become available after her husband, the previously sitting MP, inherited his father’s peerage.
You can read more about all the women who have ever been elected as MPs here.