Perhaps surprisingly, a number of MPs who had opposed women’s suffrage came out in favour of women being MPs in 1918. Among the converts were former Prime Minister H H Asquith, who said ‘You have the camel; you ought not to strain at the gnat’, Charles Hobhouse, and Arnold Ward, who asked in Parliament, ‘What use is there to retreat to a perfectly untenable line of trenches in the rear…?’
Arnold Ward’s mother Mrs Humphrey Ward (Mary Augusta Ward) was well-known not only as an author but also as the president of the Women’s National Anti-Suffrage League. Arnold Ward did not stand at the 1918 general election; presumably this family connection would not have helped endear him to new women voters.
Another convert was J D Rees (John David Rees). Rees was a colonial administrator with many years of service in India before being elected to the House of Commons in 1906. He declared:
Before the late Reform Act was passed, women’s suffrage was supported by Radicals, Reformers, Socialists, and Sentimentalists. The last is a large class, for Members incline to fall into the hands of the dangerous Delilah, who is sufficiently strong to shear Parliamentary Sampsons of their sense… The fact is that they opposed woman suffrage on the ground of sex, but, once that bar is removed, there is no further ground, I respectfully submit, for imposing any bar upon the other sex, as to the offices which they should be able to fill in this country.
Rees died a few years later in 1922 at the age of 67 in a rather unusual way; he fell from the London-Glasgow night express train at Chesterfield. The coroner concluded, ‘He might have awakened, and in a semi-dazed condition, opened the outside door thinking that he was going into the corridor,’ despite the fact he would have had to have turned the lock twice to do so. Lady Rees said that ‘Sir John was singularly unobservant of anything in the way of mechanical contrivances. He always muddled them, and it was quite a joke in the family. He seemed to have no mechanical feeling at all.’ The verdict was accidental death.
Parliament and Women in the early 20th century 
Reminds me rather of ex-Irish Unionists after 1922, some of whom tried (without much success) to participate in the new order in the Free State, on the basis that independence was a done deal, and no amount of campaigning was going to reverse it.
A most interesting parallel! I suppose history is full of such groups who have tried to backtrack from previously entrenched positions. Some more successfully than others.