Progress comes despite more firms looking to “weed out” costly or ineffective diversity goals amid a string of companies scaling back initiatives in the US, the boss of the FTSE Women Leaders Review said.

New data from the report shows that women now occupy 43.4% of boardroom positions across FTSE 350 companies.

This is up from 42.1% last year, and marks a steep increase from the 24.5% representation recorded in 2017 when the report was launched.

It also means listed companies continue to exceed the 40% voluntary target set by the review.

Vivienne Artz, chief executive of the FTSE Women Leaders Review, said a lack of resistance to diversity initiatives among the biggest UK corporates had propelled change in recent years.

She told the PA news agency: “You can’t ignore the fact that there’s a lot of questioning going on, particularly from across the ocean, in relation to DEI (diversity, equality and inclusion).”

But she said the organisation was “really pleased and impressed” with the willingness of companies to share their data, “so we haven’t encountered any resistance in the UK”.

The latest report comes as a number of large businesses in the US, including Google, Meta, Amazon and McDonald’s, have scaled back diversity programmes amid political pressure after Donald Trump’s presidential election victory.

Ms Artz said companies that were setting diversity targets “to look good” were “probably having an existential crisis” over DEI programmes.

But she said it could be “healthy” for firms to review their initiatives and “focus on what is actually working to help the business versus fluffy stuff, extra stuff, things that actually might be more irritating than effective”.

“I think it’s helpful to weed out those practices that are not working,” Ms Artz added.

Meanwhile, the analysis also found that the proportion of women in leadership positions increased to 35.3% across FTSE 350 firms, from 34.5% the previous year, as of the end of October 2024.

This spans executive positions including chief executive and chief finance officer, as well as those directly reporting to the leaders.

But on the FTSE 100, the number of female chief executives decreased from 10 to nine, remaining “few and far between, with little progress in a decade”, according to the review.

There were 28 female finance directors and 16 chairs on the FTSE 100.

About 100 of the top 350 listed companies still had fewer than a third of their leadership positions occupied by women.

“Whilst FTSE 350 company boards are now gender-balanced, sustained effort and determination is required to achieve the 40% target for women in leadership by the end of this year,” Ms Artz said.

The listed firms with the highest proportion of female leaders include retailers Marks & Spencer, Next, and Burberry, and publishing giants Pearson and Bloomsbury, which all have more than 50% female representation.

Those at the bottom of the rankings include miners Fresnillo and Antofagasta, and Games Workshop and CMC Markets, which all have less than 25% female representation.

Some private companies such as chemicals giant Ineos, parcel firm Hermes and wholesaler Bestway have no women on their boards.

Across the G7 – the group of seven of the world’s most advanced economies – the UK’s FTSE 350 ranks in second place, behind France, for female boardroom representation.

France has gender quotas for its top 40 company boardrooms, while the UK has voluntary targets.

Chancellor Rachel Reeves said: “The UK is leading the charge for gender equality in boardrooms, but we cannot rest on our laurels.

“We must break down the barriers that stop many women being represented in decision-making roles, so that top talent reaches the highest levels of leadership in businesses driving economic growth across Britain.”