The Representation of the People Act 1918, passed on 6 February 1918, extended the franchise in parliamentary elections, also known as the right to vote, to women aged 30 and over who resided in the constituency or occupied land or premises with a rateable value above £5, or whose husbands did. In March 1918 Swire Smith, the LiberalMP for Keighley died, causing a by-election on 26 April. There was doubt as to whether women were eligible to stand for parliament. Nina Boyle made known her intention to stand as a candidate for the Women's Freedom League at Keighley and, if refused, to take the matter to the courts for a definitive ruling. After some consideration, the returning officer stated that he was prepared to accept her nomination, thus establishing a precedent for women candidates. However, he ruled her nomination papers invalid on other grounds: one of the signatories to her nomination was not on the electoral roll and another lived outside the constituency. The Law Lords were asked to consider the matter and concluded that the Great Reform Act 1832 had specifically banned women from standing as parliamentary candidates and the Representation of the People Act had not changed that. Parliament hurriedly passed the Parliament Act in time to enable women to stand in the general election of December 1918. The act ran to only 27 operative 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", and is the shortest UK statute.
During the debate of the bill, Lord Islington explained the apparent discrepancy that women could sit in Parliament at 21 but could not vote until they were 30:
"...the age of thirty, which was prescribed for enfranchisement of women, was made not because women of a younger age were considered less competent to exercise the vote, but rather because the inclusion of women between the ages of twenty-one and thirty might lead to women-voters being in a majority on the Register, and this was considered, too drastic a departure in the realms of constitutional experiment. Therefore the embargo on any woman below the age of thirty was placed in that measure. In the case of eligibility to Parliament, this age condition is not necessary. The whole question of age, suitability, and competence can safely be left, and should be left, in the hands of the electorate to decide..."