Less than a quarter of new appointments to FTSE 100 boards in the six months to March 2016 were women, the lowest level since 2011, according to a report published on Thursday.
The Female FTSE Board Report by academics at Cranfield University, City University London and Queen Mary University London showed that the overall percentage of women on FTSE boards has increased compared to March 2015, but the rate of progress has slowed down.
The percentage of women on FTSE 100 boards reached 26%, and 20.4% on the FTSE 250 boards, as of March 2016.
Leading the field is drinks company Diageo, owner of brands including Guinness, Smirnoff and Baileys, which has five of 11 boardroom seats (45.5%) occupied by women. Next and Kingfisher tie for second place with 44.4% women in the boardroom.
But overall, Britain?s biggest firms need to make faster progress on gender equality to meet the 33% board target by 2020 as set out in the Davies report.
Mervyn Davies, a former trade minister, originally asked FTSE 100 businesses to ensure that 25% of directors were women. He has since extended this to all firms in the FTSE 350 and called on them to reach a target of 33% by 2020.
This target requires a constant turnover in the boardroom, with an appointment rate of one in three board positions going to women. Yet in the past six months fewer people have been leaving and joining boards, and the percentage of new appointments going to women has fallen below the one in three required to meet the 33% target.
Commenting on the report, the Government welcomed the fact that many boards have already met or exceeded the target. But it said that a ?renewed push? is necessary to help increase the pace of change.
A new review on women in senior leadership will ?focus on ensuring the very best of female talent make their way up the pipeline by removing barriers to their success?, the Government said. It will be led by Sir Philip Hampton, chair of GlaxoSmithKline, and Dame Helen Alexander, chair of UBM.
?In order to hit the 33% board target by 2020, chairmen and search consultants must ensure the board appointment process remains robust, transparent and gender-inclusive,? said Susan Vinnicombe CBE, Professor of Women and Leadership at Cranfield University and co-author of the Female FTSE Board Report.
Dr Ruth Sealy, senior lecturer in Organisational Psychology at City University London and co-author of the report, added:
?For change to be sustainable, we must focus on the pipeline and ensure that women can progress through senior management ranks. Only 19.4% of FTSE 100 executive committee members are women, and women hold only 10% of the most important senior executive and operational roles on these committees.?
Dr Elena Doldor, lecturer in Organisational Behaviour at Queen Mary University London and co-author of the report, concluded:
?Companies must do more to support women?s careers below board level. Our research shows that rigorous gender metrics and voluntary targets are effective tools that companies can use to redress their gender balance and achieve cultural change.?