The Equality and Human Rights Commission (EHRC) has found that more than 60% of FTSE 350 companies and almost half of FTSE 100 companies are failing to meet the 25% target of female representation on boards.
Three quarters of FTSE 350 companies have two or fewer women on their boards, while 40% have one or fewer, the EHRC revealed.
Only 6% of 350 organisations have more than three women on their boards, while 96% have three men or more.
The report added that fewer than half increased female board representation in recent years.
According to the EHRC, “old boys’ networks” are still being used widely and are limiting the diversity of the candidate pool.
Nearly a third of companies largely rely on the personal networks of current and recent board members to find new candidates while most companies use virtually no open advertising of roles.
Although three-quarters of companies have a board diversity policy only just over a third of those set concrete objectives or targets to increase the number of women on their board while the majority of companies undertake no specific activities to encourage applications from women for senior level or board appointments in the recruitment process.
Laura Carstensen, equality and human rights commissioner, highlighted that top boards are still “blatantly white and male” and “inexcusable and unacceptable” variation exists between companies despite progress being made by top firms to reach the target set by Lord Davies last year.
"The good work of a forward thinking minority masks that many top businesses are still only paying lip service to improving the representation of women on boards,” she added.
The position is even worse for executive posts. Almost three out of four FTSE 100 companies and 90% of FTSE 250 firms have no women in top roles.
The report also found that men outnumber women in senior position in the FTSE 350 by a ration of around 4:1.
"The best companies are showing that having talented women on their boards is boosting both performance and fairness,” Carstensen said.
"Unfortunately, the recruitment practices of too many businesses still remain trapped in permafrost and that's holding back women and ultimately the companies themselves.
"The recruitment process to the boards of Britain's top companies remains shadowy and opaque and is acting as a barrier to unleashing female talent."
Carstensen called for more open, fair and transparent recruitment to tackle the “alarming disparity across the FTSE 350.”
TUC general secretary Frances O’Grady agreed that the figures “made for depressing reading”.
“Despite the hard work of Lord Davies, it is clear that voluntary measures have not led to meaningful change in company boardrooms.
“The only way we will end the old boys' network is if ministers act to ensure all board posts are advertised publicly and move towards compulsory quotas for women. Without this, female board members will continue to be a rarity.”
A separate report by the EHRC found that more than three in four pregnant women and new mothers have experienced pregnancy and maternity discrimination at work.
The research, carried out in partnership with the Department for Business, Innovation and Skills, found that despite 77% of working mothers reporting potentially discriminatory or negative experiences, only 28% raised the issue with their employer and less than 1% pursued a claim to the employment tribunal.
The research also revealed that 70% of employers thought a woman should declare at recruitment stage if they were pregnant, and a quarter thought that it was reasonable to question women of childbearing age at interview about their plans to have children.
Three in four mothers that were unsuccessful in their job interviews undertaken while pregnant (where the employer had known about their pregnancy) felt it had affected their chances of success.
The Commission called on the government to take urgent action and recommended a number of proposals for change, including ensuring women have proper access to legal redress.
Caroline Waters, Deputy Chair of the Equality and Human Rights Commission said, “We simply cannot ignore the true scale of the hidden discrimination that working mothers face. This is unacceptable in modern Britain, and urgent action is needed to ensure women are able to challenge discrimination and unfairness. This is why we are calling on Government to look at the barriers working pregnant women and mothers face in accessing justice.
“We want to make workplaces fairer for everyone and get rid of outdated practices like asking women during job interviews whether they intend to have children. For businesses to thrive, they need to harness the talents, skills and experience of all employees. We are calling on employers, regulatory bodies and the voluntary sector to make vital changes needed to improve the lived experiences of British workplaces so they are the best they can be for everyone.”
Dianah Worman OBE, Diversity Adviser at the CIPD, the professional body for HR and people development, added that the findings were “shocking”.