Firms across the UK have just a few hours left to submit their gap in pay between men and women.

The findings will soon expose which companies have the biggest discrepancies when it comes to salary.

Of all the firms to have submitted their details so far, 78% are shown to have a gap - with airline Ryanair paying women 71.8% less than men on average.

Only companies with 250 employees or more have to submit their median and mean pay gap data.

This equates to roughly 9,000 businesses and public bodies across the UK.

The clock runs out at midnight on Wednesday.

By then, companies must have submitted their figures to the Government Equalities Office.

Those who fail to comply will be written to by the Equality and Human Rights Commission on April 9, giving them 28 days to publish the figures before an investigation is carried out.

This could result in a court-imposed unlimited fine.

As of Tuesday afternoon, more than 8,330 companies had submitted their pay ranges.

Of those, 78% are shown to have a gender pay gap.

The rest of the employers either have no median gender pay gap (8%) or one in favour of women (14%).

The national median gender pay gap currently stands at 18.4%.

Ryanair is the best-known company in the top 10 of those with the worst gender pay gap.

The airline pays women 71.8% less than men on average - when comparing median hourly rates, for every £1 men earn, women earn just 28p.

Ryanair says the disparity is because of the number of UK pilots it employs - 546 are male and only eight are female.

Theresa May has vowed to tackle the "burning injustice" of the gender pay gap.

In an article for The Telegraph, the Prime Minister compared the pay gap to the Suffragette campaign a century ago - adding that "major injustices still hold too many women back".

She wrote that progress is still too slow and action is needed to close the gap.

"It is essential that we do so. Most importantly, because equality for women is a right, and our whole society is the poorer as long as it remains unrealised," Mrs May said.

"There is also a clear economic imperative. It is estimated that if women and men enjoyed parity in their hours, pay and seniority at work then we could see up to £150 billion added to our GDP."