The number of women holding senior posts in politics, the law and the media has fallen compared with last year, a report suggests.
Research by the Equality and Human Rights Commission (EHRC) says that in 12 of 25 job categories studied, there were fewer women holding top posts.
Women's representation had increased in eight areas, including company directors and the civil service.
The EHRC said some women face a concrete ceiling, not a glass one.
The commission also wants more flexible working to help women rise to the top.
The EHRC says its annual study into women in top positions of power and influence across public and private sectors has showed the biggest number of reversals since the report was started five years ago.
According to the report, there are fewer women MPs, Cabinet members, national newspaper editors, senior police officers and judges, NHS executives, trade union leaders and heads of professional bodies, compared with 2007.
The number of female media bosses, MEPs, directors of major museums and galleries, chairs of national arts companies and holders of senior ranks in the Armed Forces has remained the same.
Women's representation had increased in the House of Lords, company directors, council leaders, university vice-chancellors and top civil service managers.
However, in six of these categories the increase was less than 1%.
The commission says opportunities for ambitious women to reach the top of their career are changing at a "snail's pace".
It blames Britain's business culture of long working days and inflexible working practices for discouraging women who want to both work and raise a family.
The report, Sex and Power, says: "Often women experience a draining combination of outdated working practices and a long hours culture alongside the absence of appropriate high quality affordable childcare or social care."
EHRC chief executive Nicola Brewer said: "Workplaces forged in an era of stay-at-home mums and breadwinner dads are putting too many barriers in the way, resulting in an avoidable loss of talent at the top.
"We always speak of a glass ceiling. These figures reveal that in some cases it appears to be made of reinforced concrete. "
TUC general secretary Brendan Barber said: "This survey proves that the softly-softly approach towards breaking down the glass ceiling is not working.
"A firmer approach is needed so that women can reach the top on merit, rather than by having to fight every obstacle that society puts in their way."
Harriet Harman, Minister for Women and Equality, said: "We have made great progress but we still have a long way to go."
3. ceiling (價格,工資等)最高限度;最大限額
5. executive經理;業務主管[C]行政部門[the S][G]
12. break down失敗;故障