The male-dominated world of company boards is slowly but surely changing.

The number of women on boards is increasing in the FTSE 100 and, crucially, in the FTSE 250.

FTSE 250 companies have generally lagged behind those in the FTSE 100 when it comes to board diversity as they are less well known and therefore face less pressure to change.

Yet over the past 12 months, FTSE 250 companies have seen around 30 per cent of new appointments go to female directors, the benchmark figure for substantive change.

Over the same period, FTSE 100 has reached 27 per cent of appointments.

In 2011, a report prepared by Lord Davies of Abersoch found that women made up just 8.5 per cent of FTSE 250 company boards in the UK.

Today the figure sits at 15 per cent, with only 51 FTSE 250 boards remaining all male.

The Cranfield School of Management recently published a report saying that the 15 per cent figure is the highest since the organisation began monitoring board diversity in 1999.

Professor Susan Vinnicombe, director of the Cranfield International Centre for Women Leaders and co-author of the report said: “We are definitely seeing a cultural shift taking place within UK business.

“We have seen progressive steps taken by many stakeholders to increase the level of female talent at the most senior levels of the UK’s top companies and we are starting to see a shift in perceptions from chairmen and chief executives.”

Despite improvements, the Cranfield report found that while 82 per cent of their FTSE 250 sample recognise the need for greater boardroom diversity, only 18 per cent had a clear policy and just 14 per cent have set measurable targets.

The report did, however, find that 24 per cent of these companies now include diversity in their evaluation processes.

Monitoring and transparency are key for the continued progress of women in the boardroom.

Maria Miller, Minister for Women and Equalities, said: “This new research shows that we’ve made unprecedented progress in increasing the number of women on boards following Lord Davies’ report in 2011.

“It is good to see the pace of change in the number of board appointments in the FTSE 250 have been higher than in the FTSE 100.”

She continued: “However, FTSE 250 firms need to ensure that they are producing and publishing policies on boardroom diversity.

“I want firms to redouble their efforts on both fronts to ensure we are enabling women to fully contribute their talent.”

Lord Davies also commented on the Cranfield report.

“There are real grounds for optimism in this report, not least the case studies and examples of good practice from companies across a range of sectors,” he said.

“They know that using all of the talent available to them, fostering the right mix of skills and backgrounds to provide different perspectives and customer insights, is not an optional extra. It is a compelling business need.”