Although there has been an increase in the number of women appointed to board-level positions in the past year, the rate of improvement is slower than that laid out by Lord Davies in his report on boardroom diversity 12 months ago.
A year on from the publication of the Davies Report, its author welcomed the progress that has been made, but warned that the rate of change has to increase if compulsory quotas are to be avoided.
Lord Davies said: "I believe that we are finally seeing a culture change taking place right at the very heart of British business in relation to how women are seen within the workforce.
"Some excellent work has taken place... However, I must also emphasise that efforts need to be ramped up and the speed of change accelerated if we're to avoid government interference."
The Davies report originally set a target of 25% of board-level positions at FTSE 100 companies to be held by women by 2015. That figure currently sits at 15.6%, an increase from 12.5%.
However, despite what the Department for Business, Innovation and Skills (BIS) referred to as the "largest ever annual increase in the percentage of women on boards", fewer than one directorship in 10 (9.6%) within the FTSE 250 is currently held by a woman.
Last week, EU justice commissioner Viviane Reding announced the launch of a consultation on the introduction of compulsory quotas on the numbers of women appointed to board-level positions, which she said would be necessary if companies did not voluntarily increase levels of boardroom diversity.
The "Women on boards: one year on" report looks at the progress made in the 12 months against each of Lord Davies' 10 original recommendations.
According to BIS, 17 companies in the FTSE 100 have already reached the 25% target and a further 17 are between 20% and 25%. In addition, 21 FTSE 250 companies have reached the 25% target and a further 28 are between 20% and 25%.
BIS added that, over the next year, Lord Davies and his panel will prioritise work towards reaching the 25% target in FTSE 350 companies, and on building a sustainable, credible supply of board-ready women through training and development initiatives.
The "Women on boards: one year on" report is available from the BIS website.