Why some women gained the vote in 1918

The Representation of People Act became law in February 1918. From that point on women over 30, who were occupiers of property or married to occupiers, were entitled to vote.

This was seen as a major success for women's suffrage and was also popular with the general public. The Act was not such a success for women under 30. They would have to wait another 10 years before they received the same rights.

Why it took so long for women to gain the vote
Women had to overcome many obstacles and face many challenges to gain the vote. Like middle and working class men before them, they had to convince Parliament to extend the franchise to them. People who have privileges are always reluctant to give them up, and this was an even bigger gamble for MPs than giving votes to some extra men - after all, giving women the vote on the same terms as men meant more than doubling the electorate. Politicians in both of the main parties were worried that the women might vote for their opponents.

Both socially and legally, women were regarded as inferior to men in the 19th century. This was changing, but too gradually to allow the campaign for the vote to succeed quickly.
There were divisions among women - some of them agreed with the view that women should not take part in politics, even that they would not be able to understand politics.
The tactics of the WSPU received massive publicity but much of it was negative, leading to arguments that women who acted like this did not deserve the vote. At one point, Churchill proclaimed that "their cause has marched backwards".

The very public disagreements between the suffragist and suffragette leaders, and later even within the suffragette movement, did not help to create a coherent campaign.

At the height of the campaign, the Liberal government had many other issues and crises to deal with - passing their social reforms, trouble with trade unions, the dispute between the Lords and the Commons over the Lords' rejection of the 1909 Budget, the naval arms race with Germany, the increasing likelihood of war in Europe, and the Home Rule debate leading to violence in Ireland. This meant that the suffrage campaigners were competing with all these issues for the government's attention.

Fancy learning more?
http://www.parliament.uk/about/living-heritage/transformingsociety/electionsvoting/womenvote/overview/thevote/

http://www.bbc.co.uk/bitesize/higher/history/britsuff/vote/revision/2/

https://en.wikipedia.org/wiki/Representation_of_the_People_Act_1918

http://www.parliament.uk/about/living-heritage/transformingsociety/electionsvoting/womenvote/overview/thevote/