Women now make up 17.4 percent of the FTSE 250 boards according to the latest progress report from the Cranfield School of Management.
This is an increase of 124 percent since Lord Davies' report into women on boards was published in 2011.
Davies advised the FTSE 100 and FTSE 250 to ensure 25 percent of boards were made up of women by 2015 and 2016 respectively, a target that Cranfield academics predict is on track.
The top 250 listed companies need to bring in 150 more women in the next two years to comply with the voluntary targets set by Lord Davies, the report stated.
However, ComputerworldUK has previously reported that the top five listed companies have just two permanent female executives between them. The sixteen other women on the board are non-executive directors, which typically means they have not been employed in the company but brought in at a high-level.
The top five listed technology firms have no permanent female board members and just three non-executives.
Overall, less than 10 percent of leading UK companies have women in permanent executive roles. This is figure is double the international average.
In the report, Alistair Lyons, chairman of Serco, an IT services supplier, stated: "A third of our board is female but these are all non-executive members. I believe there is an increasing recognition that the real issue is not board composition but the balance of women in senior executive positions. It is this that will provide the opportunity for talented women to become directors, both executive and non-executive, and it is here that, in my view, we should be focusing.
"Within Serco we are, therefore, maintaining our focus on diversity across our management team. At present, 12.5 percent of our senior managers are female and we will be seeking to increase this over time"
Director of the Crandfield international centre for women leaders said: "It was a landmark day earlier this year when the last all-male board in the FTSE 100 finally appointed its first woman director. With only 28 out of the FTSE 250 boards remaining all male, we are beginning to see what we hope is lasting change when it comes to gender diversity in Britain's boardrooms."
Dr Ruth Sealy, a City University lecturer and the report's co-author said: "What is most encouraging is that, finally, we are seeing the percentage of female Executive Directors starting to rise, after having stagnated at 5-6 percent for many years. In the FTSE 100, 24 women now hold 8.4 percent of executive directorships."
The report studied FTSE 100 companies' annual reports to analyse its gender diversity policies.
Improvements and concerns from last year's report include:
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