The days of all-male boards in the FTSE 100 Index have finally ended with the appointment of a female director at commodity giant Glencore.
The arrival of Canadian mining executive Patrice Merrin means the Swiss firm is no longer the only blue-chip firm without a woman on its board.
Business Secretary Vince Cable has praised the efforts of businesses in boosting boardroom diversity since the Government-commissioned Lord Davies review at the start of 2011, when women accounted for 12.5% of directors of FTSE 100 firms.
The percentage stood at 21.5% in May.
Mr Cable said: " This is a historic day for the FTSE and for the reforms I've been pushing for to ensure that there is more diversity in the talent running our biggest companies.
"Huge progress has been made on this agenda since 2010 and from today every single top 100 company listed on the London stock exchange now counts a woman on their board."
Pressure intensified on Glencore at its AGM in May when a group of shareholders led by Aviva Investors threatened not to approve its annual report because of the make up of its board.
Chairman Tony Hayward, who is the former boss of BP, told shareholders he would appoint a woman to the company's board by the end of the year.
Ms Merrin joins an eight-strong Glencore board, which takes the firm's female representation up to 12.5% at a single stroke.
She is a non-executive director of US platinum and palladium miner Stillwater Mining Company and was a director of CML Healthcare from 2008 to 2013, including a period as chairwoman.
Mr Hayward said: "Patrice's in-depth experience of operating across the resources sector will help strengthen the board's ability to work with the opportunities and challenges presented by the global extractive industry."
In January, Mr Cable wrote to the heads of the country's biggest public firms and said that 25% of the places on FTSE 100 boards should be filled by women by next year.
He added: " Much more needs to be done of course to tackle diversity in the FTSE 250 and to fix the pipeline of women working their way up to the top of businesses to become the leaders of tomorrow.
"But for today, let us celebrate this important landmark achieved working hand in hand with business, not by imposing tokenistic targets, which other countries have favoured."