The Conservative Party should use positive discrimination to ensure an increase in the number of women MPs, a former shadow cabinet minister has argued.

Speaking to the BBC, Andrew Lansley called for a quota system, in which half of all candidates offered to local constituency associations would be women.

There are currently 14 women MPs on the Conservative benches, compared to 150 men.

No increase in the proportion of women MPs after the next election would be "unacceptable," Lansley argued.

At the last election 16 per cent of the candidates offered to constituencies were women and 16 per cent of the candidates selected were women - which he said proved the success of quota systems.

The move would also prove that the party was prepared to modernise.

"It will not be acceptable if, after the next election, out of 250 or 300 Conservative MPs, a small proportion were women," he told the BBC Radio 4 Today programme on Monday.

He will be making his case to a fringe meeting at the party's conference in Bournemouth on Tuesday.

This is the second time that Lansley has made the call for a quota system.

In July last year, his campaign was backed by Theresa May, now party chairman.

"What I have spoken about in the past is having a 50-50 split on a candidates list for a certain number of seats, a 50-50 gender split, with obviously a good number of ethnic minority candidates throughout that," she said.

"We have been making some progress with what we are doing so far. But obviously we will continue to monitor the situation."

However, of the 28 candidates already selected for the next election, just six are women while none are from an ethnic minority background.