Britain's biggest companies need to "get their house in order" by appointing more women to executive positions, the author of a landmark report into gender inequality in the boardroom has said.
The target set by Lord Davies's 2011 report for women to make up 25% of FTSE 100 boards by the end of 2015 has been met, with the figure currently standing at 26% and none of the boards remaining all-male.
But some 260 of the 286 women on boards are non-executive directors, with only a handful holding the key decision-making positions on executive committees.
Lord Davies said there had been "a cultural change in the UK corporate scene" over the past four years, but said it was time for big companies to make similar progress in the top jobs.
But he dismissed calls for official mandatory quotas of female bosses, insisting that it was best to take the same voluntary approach with executive posts as his report did with boardrooms.
Lord Davies told BBC Radio 4's Today programme: "The focus of our work was on fixing the boardroom. We've done that and there's very few all-male boards left.
"There's been a cultural change in the UK corporate scene, which was totally dominated by men. That is not the case today. We now need to see the same change, through a voluntary approach, in the executive committee structure of big companies and small companies."
Lord Davies said he was "delighted" with the progress made towards gender equality, which had seen the proportion of the top 100 companies with no women on the board fall from 21% to zero over the past four years.
He rejected suggestions that companies were "padding" boards with female non-executives for public relations purposes, insisting the women appointees were qualified for their posts.
And he said the key incentive to promote women was the impact they can have in business terms.
"It's about business results," said the former chairman of Standard Chartered bank, who served as a trade minister in Gordon Brown's government. "The more diverse the group is at the top of the company,the better the results.
"I think also at the top of the company you should represent your workforce and your consumers. People forget that 51% of the working population in the UK is female. These top companies have now got to put their house in order and fix the executive committees.
"We've made it very clear in the report and in engagement with headhunters, chairmen and CEOs, the best route to success is the voluntary approach. I would expect - and I'm very confident - over the next five years to see the same change in executive committees as we've seen in boardrooms."