DAVID Cameron will today risk infuriating Tory diehards when he unveils further plans to increase the number of female candidates at the next general election.

While he will stop short of the all-women shortlists controversially adopted by Labour, the Tory leader will tell constituency parties that they must include at least two women on a four-person shortlist when selecting candidates.

Mr Cameron, in a sop to critics who have railed at the A-list of candidates handed down from on high, will propose that more of the membership will be involved at an early stage.

Implicitly acknowledging that earlier efforts to increase the number of women have not been effective, largely because constituency parties have ignored the leader's entreaties, the party hierarchy is now making it clear that constituency parties will not be allowed to ignore them.

For the next round of selections, associations with fewer than 300 members will be expected to select their candidate through an open primary, whereby anyone who is on the electoral register is free to go along to select the candidate.

This idea, imported from the United States, is an attempt to reach out beyond what may be regarded as an out-of-touch association.

Where there is not an open primary, the full membership will select a shortlist of four, of which two must be women. In certain circumstances, the shortlist could be shorter, but must always comprise at least 50per cent women.

Mr Cameron, whose speech will coincide with a review of the A-list, is adamant that the party's representation in parliament must change.

He will say: "Last year, Conservative Party members voted for change. In my leadership campaign, I said we had to end the scandal of women's underrepresentation in the Conservative Parliamentary Party.

"The conversation inside our party must be closer to the conversation in our country: more female Conservative MPs will lead to better policies and a party that is more in touch with modern Britain.

"I am encouraged that the proportion of women selected as candidates under our new process is already three times greater than the proportion of female Conservative MPs today. This shows that real change is taking place within our party.

"But we need to go further, and we need to go faster. So we are taking further steps today to increase the number of women candidates. I want to see more women candidates selected, and I want to see them selected on merit - through a proper, professional process that accurately assesses all the skills needed to be a successful MP in the 21st century. That is the basis of the changes we are announcing today, " he added.

Earlier this year, in a speech to the Equal Opportunities Commission, Mr Cameron gave a commitment to make sexual inequality history and highlighted the need for more flexible working patterns, childcare, and equal pay, in what was seen as a clear attempt to woo the female vote at the next election.