Commercial insurers and brokers in the United Kingdom have pledged to reduce the pay gap between male and female employees after government-mandated reporting revealed big differences in average pay and bonuses for men and women working in the insurance sector.

The financial and insurance sector fared badly compared with other sectors, reporting the highest pay gap on a mean basis at 25.9%, ahead of construction at 21.8% and mining and quarrying at 20.8%, according to an analysis by Staffmetrix Ltd., an Edinburgh, Scotland-based consultancy.

The average mean gap for all companies reporting was 14.5%.

A Business Insurance analysis of 45 companies in the commercial insurance and reinsurance sector reveals that the average difference in hourly pay, calculated on a mean basis, was 37.6% lower for women, and the average bonus was 64.9% lower for women. Brokers reported the biggest gaps. None of the insurance sector companies reported a pay or bonus gap in favor of women.

All U.K. employers with more than 250 employees were, for the first time, required to publish their gender pay gaps and bonus gaps on a mean and median basis. The requirement stems from a 2010 law, but the first reporting deadline was last month.

When reporting the pay gaps, many insurers and brokers said that while they pay men and women equally for performing the same jobs, they have more men than women in senior positions.

In the commentaries accompanying the reports, most of the firms pledged to take steps to reduce the gaps, such as introducing mentoring programs, working to address unconscious biases and implementing processes to ensure that women are considered for promotion to senior management positions.

The insurance sector will need to change its employment culture to reduce the gaps, experts say.

Sian Fisher, CEO of the London-based Chartered Insurance Institute, the U.K. insurance industry’s professional association, said the organization would develop and share best practices “of what works practically” on how to address the gap.

Tackling biases is one way that the gap can be closed, she said.

“It is all too easy to make assumptions about women that may have a negative effect on their career and earning potential,” Ms. Fisher said in a CII report on the issue. “For example, you may assume that a female employee is unable to attend an important conference abroad because they have children.”

Culture is a significant factor in creating promotion barriers for women, said Heidi Watson, employment partner at law firm Clyde & Co in London.

The U.K. insurance market, particularly in London, remains heavily dependent on relationship-building that is often developed via activities that discourage inclusivity, she said.

“Firms need to think much more broadly about what it means to build relationships and facilitate that beyond providing a budget to taking contacts to the pub or to a corporate (soccer) match,” Ms. Watson said. “In the modern workplace, there are myriad ways to develop relationships which also work around people’s personal lives.”

“The next generation of underwriters and brokers, regardless of gender, will expect to have the flexibility to manage relationships in a more creative way than has happened in the past,” she said.

Insurance historically is very male-oriented profession in the U.K., but much can be done to speed up the process of achieving pay parity in the workplace, said Rodney Bonnard, U.K. head of insurance at Ernst & Young Global Ltd. in London.

Initiatives that the industry should continue to drive and develop include allowing and encouraging flexible working arrangements, and establishing networking, mentoring and development programs for women and men, he said.

“There are a number of exceptionally highly regarded women in insurance, but closing the gender pay gap is not only about increasing the number of women in senior leadership roles,” he said. “It’s about challenging stereotypes, for example by boosting the number of men in administrative roles.”

“Reverse mentoring is also an excellent way for senior managers to get an understanding of how the culture feels for a more junior member of the team, of whatever gender,” Ms. Watson said.

“I prefer to see this as a modernization issue rather than a gender issue — creating an inclusive culture for the modern age,” she said.