Britain's top companies have made "significant progress" towards meeting a voluntary target of having a third of board positions filled by women by 2020, a new report indicates.
A government-backed review revealed that 28% of board positions in FTSE 100 companies are now held by women, up from 12.5% in 2011.
But Sir Philip Hamilton, who chaired the review along with the late Dame Helen Alexander, said more needed to be done to make the UK a world leader on gender diversity at the top of business.
He expanded the voluntary 33% target to senior leadership positions to include FTSE 350 companies and challenged them to meet it by the year 2020.
The review found that there are only 10 all-male FTSE 350 company boards at present – down from 152 in 2011.
However, Hamilton said at least four out of 10 appointments to senior positions will have to be filled by women over the next three years if FTSE 350 firms are to meet their target.
"Some of our largest companies have made significant progress towards meeting these challenging targets, both on boards and in their leadership teams," he said.
"We should be seeing all FTSE companies now making strides to improve the gender balance at the top."
Business Minister Margot James said: "Businesses have made great strides in recent years to increase senior female representation and now is a time for the business community to step up to the challenge to make the UK a world leader on this important issue.
"We have seen time and time again that our most successful companies are those that champion greater diversity and inclusion, and our largest companies are stepping up their efforts on this issue in order to reap both the societal and economic benefits."
The review comes days after research from the World Economic Forum revealed that Britain was among the most improved countries in gender balance rankings over the past year.