The Big Question: How will all-women shortlists change the face of Parliament?

Why are we asking this now?

David Cameron has indicated that he may impose all-women shortlists on constituency associations who will be choosing parliamentary candidates at the last minute, as next year's general election approaches.

"From January, we move to what we call our by-election procedure, which is that if any MP stands down either shortly before that date or after that date, the central party provides the shortlist to the association," he told the Speaker's Conference in the Commons yesterday.

"It's my intention that if we continue as we are, that some of those shortlists will indeed be all-women shortlists to help us boost the number of Conservative women MPs and also to recognise the fact that although about 29 per cent of our candidates are women, there are many very very good women on our priority list of candidates who haven't yet been selected and I want to give them the chance to serve in Parliament, so that's my current intention."

Is this something new?

All-women shortlists are not new. Labour introduced them 14 years ago, to boost the number of woman MPs on the Labour side, and have been using them again during the current round of selection of parliamentary candidates. But for the Conservatives, this is something new, and very controversial. It is a sign that David Cameron badly wants his party to have a modern look.

How did all-women shortlists originate?

The impetus for women-only lists came from certain trade unions with a high proportion of union members, such as the old white collar union, the Manufacturing, Science and Finance Union (MSF). In 1993, the then Labour leader John Smith wanted to remove the union block from internal party elections, but to do that he needed the backing of big unions, so he offered them all-women shortlists on condition that they backed him over the block vote. Party officials then imposed women-only contests in half the vacant, winnable Labour seats, and at the next election, in 1997, the number of women Labour MPs leapt from 37 to 101. They were commonly known as "Blair's babes".

Isn't it illegal to exclude men from a shortlist?

Employment law makes it illegal to discriminate against men in the workplace as well as against women, but this was not thought to apply to the selection of candidates until two men, who actually had no realistic chance of being selected by Labour under any system, decided to complain to an industrial tribunal, which ruled in their favour, in January 1996. After that, there were no more all-women shortlists for six years, and at the 2001 general election, the number of Labour women MPs dropped to 95.

So how can there still be all-women shortlists?

In 2002, the Government passed the Sex Discrimination (Elections) Act, specifically to make it legal for political parties to use all-women shortlists. The outcome was that 30 Labour candidates were chosen from all-women shortlists, and 23 of those were elected to the Commons.

Do the Liberal Democrats use all-women shortlists?

In 2001, a proposal went before the Liberal Democrat annual conference to impose an all-women shortlist in each constituency where a sitting Lib Dem was retiring. At that time, the Lib Dems had 47 male and five female MPs. The proposal was rejected on the grounds that it was illiberal, though some of its opponents also feared that there were not enough able women prepared to put themselves forward. At the last election, in 2005, the number of women on the Lib Dem benches went up from six to 10, out of 62, though one, Patsy Calton, died only weeks later, and was succeeded by a man.

What is the Conservative view?

Until recently, the Conservative Party has adamantly opposed all- women shortlists. The most common reason given by opponents is that they believe candidates should be chosen on merit, not on the basis of gender. But that is not the only reason. There is also the traditional independence of constituency associations, who object to central interference in the selection process. Another reason, perhaps not as strong now as it was 10 years ago, is a sexist prejudice against women MPs. Local associations often expected two for the price of one: an MP, and an MP's wife, who would both play an active role in the local association. At the 2005 general election, the number of Tory women MPs reached what, for them, is a record – 17, out of a total of 196 – less than one Tory MP in 10.

Is it only men who oppose all-women shortlists?

One factor that has deterred David Cameron up to now is the vehement opposition of some Tory women. Ann Widdecombe, the best known woman Tory MP, argues that the shortlists would create two classes of women MP, those who have reached Parliament on their merit, and those who needed to have their path cleared by preventing men from competing with them. "Every woman MP has to be able to look every male MP in the eye and know that she got there on the same basis as they did," she has said. "Neither Margaret Thatcher nor I needed this kind of help to get into Parliament." Nadine Dorries, one of the MPs newly elected in 2005, said that it fills her "with horror" to think that "people who meet me may think that I was selected in an undemocratic manner from an all-female short list."

So are there going to be as few women Tory MPs as ever?

With or without all-women shortlists, there will be more women on the Tory benches next time, and not only because there will be more Tory MPs than any time since the 1990s. Local associations have been more willing than ever before to select women, so that David Cameron was able to tell MPs that 29 per cent of their candidates are women. That implies that if the Tories win a one seat majority in the next Parliament, the number of women Tory women will more than treble to about 60. But that still does not compare with Labour's record, which is why Cameron is considering all-women shortlists to bump up the total.

Will Cameron get his way?

In the run-up to a general election, David Cameron will be in a strong enough position to overrule opposition from local associations if that is what he is determined to do, but he will have a fight on his hands. The editors of the influential ConservativeHome website were quick to voice opposition yesterday. They argued that all-women lists "would be an unacceptable departure from Conservative concepts of meritocracy and trusting people" and they asked: "Why should we believe the Tory leadership on their promises to localise power if – yet again – they centralise power over candidate selection?"

Are all-women shortlists the best way to beat the imbalance in Parliament?

Yes...

* Sexist prejudice persists locally in some political parties; this may be the only way of countering it.

* Merit, in an MP, is not the same as having the sharp elbows needed to see off the competition.

* No one has yet found a more effective way to increase the number of women MPs.

No...

* Tough women like Margaret Thatcher, Barbara Castle and Mo Mowlam fought off men to get selected.

* All women shortlists are a method by which the party leadership overrides local wishes.

* What next? All gay shortlists, all Muslim shortlists?