Britain’s largest listed companies are failing to increase the number of women on their boards despite a Europe-wide push to get more women to top management positions, figures published on Tuesday showed.

The BoardWatch data showed that 17.3 percent of directors in the FTSE 100 are now women, barely an increase from the 17.2 percent rate in August last year, the slowest growth since new voluntary targets were set by former Trade Minister Mervyn Davies in 2011.

While 34 percent of all new appointments since March 2012 have gone to women, this failed to make a mark on the total number as there were relatively few new appointments.

“Overall, 2012 showed good progress,” said Jane Scott, UK Director of BoardWatch. “But the very latest data reveals a plateau in the last quarter, where the rapid growth seems to have fizzled out,” she added.

Davies, who published a review of the issue in 2011 commissioned by the coalition government, set a target that all FTSE 100 companies should have at least 25 percent female board members by 2015.

The debate around boardroom equality intensified in September when the European Union laid out a plan to force companies to have a minimum of 40 percent women on non-executive boards by 2020.

The plan for a quota was subsequently scaled back to an “objective” after facing opposition from Britain and Germany, which could only force firms to pick equally qualified women over men.

So far in Britain, 27 companies of the FTSE 100 have achieved the UK target, with women holding 17.4 percent of directorships overall, up from 12.5 percent in 2010.

Fashion firm Burberry has the highest proportion of women at 38 percent, followed by 36 percent at spirits group Diageo, where Davies is the senior non-executive director.

Seven firms in the top flight, mostly in the mining and chemicals sectors, including Antofagasta and Glencore, still have all-male boards.

Although the targets and figures include both executive and non-executive board members, some see the former as the more important measure.

BoardWatch figures show women hold 5.8 percent of all executive board roles as of end-February 2013, compared with 5.5 percent in 2010.

Despite the recent plateau, Britain seems to be marginally ahead of other countries on the issue; in the European Union, women held 15.8 percent of board seats as of October 2012, while the figure was 16.6 percent on the Fortune 500 in the United States in December.