The right to vote - key dates

1832 Reform Act

1867 Second Reform Act

1884 Third Reform Act 

and it was 1918 The Representation of the People Act, which finally gave the vote to all men,  and also to women over the age of thirty.

https://www.parliament.uk/about/living-heritage/transformingsociety/electionsvoting/womenvote/case-study-the-right-to-vote/the-right-to-vote/birmingham-and-the-equal-franchise/1918-representation-of-the-people-act/

The UK finally becomes more seriously democratic in 1928, when the Equal Franchise Act gives the vote to all adults, irrespective of gender