The number of women in many top jobs and positions of power has fallen, with progress on equality moving at a "snail's pace", a report said.

The annual "Sex and Power" report by the Equality and Human Rights Commission (EHRC) found that women occupied fewer senior positions in politics, the media, and the judiciary compared with last year.

"We always speak of a glass ceiling. These figures reveal that in some cases it appears to be made of reinforced concrete," said Nicola Brewer, EHRC chief executive.

Fewer women were in positions of power and influence in 12 out of 25 categories while the situation was unchanged in another five areas, the report said, blaming Britain's long-hours culture and inflexible working pactices.

There were fewer women MPs, members of the Welsh and Scottish Assemblies, senior police officers, judges, national newspaper editors and chief executives of public bodies.

However there was a rise in the number of female FTSE 100 directors, council leaders, top managers in the civil service and members of the House of Lords.

The study said it would take women 55 years to achieve parity at senior levels in the judiciary and 73 years to reach equal status in the number of FTSE 100 directors.

The Commission said inflexible workplace systems forged in an era of "stay at home mums" and "breadwinner dads" had failed to keep pace with modern living and meant that the talent of women was being squandered.

"The Commission's report argues that today's findings are not just a 'women's issue' but are a powerful symptom of a wider failure," Ms Brewer said.

"The report asks in what other ways are old-fashioned, inflexible ways of working preventing Britain from tapping into talent."