Anna Bird, acting chief executive of the Fawcett Society, said in response to the publication of the review of women in business:
"The lack of women on British boards is a stark example of workplace inequality between women and men. Many years of tapping away at the glass ceiling have left it stubbornly intact, with almost 90 per cent of boardroom positions going to men.
"Leaving business alone to tackle the problem on a voluntary basis isn't working; continuing with this approach means excluding another generation of women from the top table of business. The time has come to take radical action.
"While Lord Davies has reserved the right to introduce more prescriptive measures in coming years - if further voluntary action on the part of business fails - the Fawcett Society believes this report is a missed opportunity.
"All the evidence shows positive action through the use of quotas is the only sure fire way to ensure more women reach the boardroom. Government should set a deadline by which they will force boards to take action. Wishful thinking and encouraging words are not going to bring about the step change we urgently need.
"This is about more than workplace equality, it's about access to power. Not only are nine out of ten of our top business leaders men, there are currently only four women in the government cabinet of 23, while in parliament men outnumber women four to one. In politics, business and public life more generally, decisions which affect us all are being made with too few women in the room.
"If the government is serious about increasing the number of women on boards, and so sharing these positions of great power and influence more fairly between women and men, quotas are the way to do it."