Women now account for 20.7% of board members in the FTSE 100 firms, up from 12.5% in 2011 according to the third annual progress report into Women on Boards.

Lord Davies of Abersoch, who headed up the report, said: “The rate of change that we have seen at the heart of our biggest companies over the last 3 years has been impressive. The voluntary approach is working and companies have got the message that better balanced boards bring real business benefits. We are finally seeing a culture change taking place at the heart of British business.”

However, he added that “the eyes of the world are on us” to judge whether the voluntary approach, as opposed to regulation, will work.