Women in Epping Forest will effectively work more than one month for free this year, figures revealing the area's gender pay gap show.

Marking Equal Pay Day, the Fawcett Society welcomed a national narrowing between male and female workers' wages but warned the pandemic could "turn the clock back for a generation" of women.

Figures from the Office of National Statistics show women working in Epping Forest earned an average hourly salary of £11.66 as of April – 13% less than men, who earned £13.40.

Over the course of the working year, this means, in effect, women in Epping Forest will have worked without pay from November 16 in 2020.

Female workers in Epping Forest also earn below the median average hourly rate of £12.50 for women across the UK.

The equivalent for UK men is £14.79, meaning they earn 15.5% more every hour – down from 17.4% in 2019.

Hourly figures are used to remove the effect of overtime, while the median is used, to stop them being skewed by particularly small or large wages.

When hours worked are taken into account, the mean average full-time salary for UK women is £33,259, compared to £42,231 for men.

Therefore, the Fawcett Society is marking November 20 as Equal Pay Day this year – the day when women, effectively, stop being paid.

The gender equality charity said a fall in the pay gap is positive, but cautioned that a quarter of employers are missing from the ONS data because of disruptions caused by Covid-19.

Sam Smethers, Fawcett Society chief executive, said coronavirus poses a number of risks to women’s pay and employment which could "turn the clock back for a generation", though it will take until next year to know how significant this will be.

She added: “Mothers are more likely to have had their work disrupted due to unequal caring roles and a lack of childcare. Men are more likely to have worked under furlough, and to have had their pay topped up.

"The second lockdown looks set to hit women working in hospitality and retail hard while predominantly male-dominated sectors like construction and manufacturing are still at work.”

Pay discrimination is prohibited by law but the charity says it persists because employers can too easily hide salary information.

Other factors include women doing more part-time work, often as mothers or carers, an undervaluing of the types of work women do, a lack of women entering some well-paid careers such as engineering, and the failure to promote women within organisations.

The Equality and Human Rights Commission said reporting gender pay gap data is an important tool in combatting unlawful pay discrimination, but "meaningful action" is also needed.

A spokeswoman added: “We have repeatedly called for the Government to make it mandatory for employers to publish action plans with specific targets and deadlines alongside their pay gap data.

"This would mean that employers not only have to gather the data, but also interrogate it and put in place measures which could help create an environment where women can flourish.”

The Equality Hub, which is made up of officials from the Government Equalities Office, Race Disparity Unit and Disability Unit, said a comprehensive support package was in place for sectors that have been particularly impacted by the pandemic.

A spokesman added: "As we look to unite the country and recover from the pandemic it is key that companies embrace flexible working initiatives which have a positive impact on recruitment and the productivity of staff."