Allen & Overy (A&O) has become the second magic circle firm to reveal its gender pay gap data, with the firm’s report providing more hard evidence of the disproportionate number of women in lower-paid roles at large law firms.

The report reveals that more than 25% of London staff are women in business support roles, and that 71% of employees in the firm’s lowest-paid quartile are female – an imbalance which means that average hourly pay for male staff is 19.8% higher and average bonuses for men are 42.1% higher.

The firm’s disclosures come ahead of an April reporting deadline for all organisations employing more than 250 people.

A&O’s pay gap is less pronounced than that of magic circle rival Linklaters, which last month became the first magic circle firm to report, revealing that male hourly rates are on average 23% higher than women, with men on average receiving bonuses 58% higher than women.

A&O’s report shows slightly more men (56%) received a bonus than women (53%). Global HR director Sasha Hardman said the firm’s bonus gap was influenced by the fact that more senior roles in the upper pay quartile are held by men, while the majority of the firm’s lowest-paid staff are female.

The mean gender pay gap within the upper pay quartile – which includes associates, counsel, senior managers and directors – is 13.6% in favour of men. In contrast, women in the lower quartile of earners are paid on average 4.9% more than their male counterparts, while in the middle two quartiles, pay for men and women is broadly similar.

Hardman said: “Following [senior partner] Wim Dejonghe and [managing partner] Andrew Ballheimer’s appointments in 2016, gender diversity has been a priority area of focus. The gender pay gap report is a helpful proof point. More of the senior roles in the upper quartile [of our employees] are held by men, which impacts the bonus discrepancy.”

The firm’s report acknowledges that it has “not succeeded in retaining and promoting enough” of its best women, and that it has put strategies in place – including creating a gender advisory committee – to ensure it is making progress.

While law firms are not required to provide data about partner pay, fellow UK top 50 firm Irwin Mitchell has published the details of its gender pay gap at full equity and fixed-share partner level.

The firm’s report reveals UK male equity partners receive on average 8.5% more in gross hourly earnings – and that men make up 76% of the top-earning quartile of partners.

The only other major law firm to have announced details of a gender pay gap at partner level to date, Bird & Bird, found a pay gap marginally in favour of women, but declined to provide specific data.

Irwin Mitchell has also reported an average bonus pay gap of 12% in favour of male equity partners, although slightly more female equity partners (82%) were paid a bonus than men (81%).

Its report also shows male fixed-share partners receive on average 11.4% more on an hourly basis than women.

The proportion of fixed-share partners at the firm is broadly level, with 54% men and 46% women, but the gap is much more pronounced among the equity, where 73% of partners are male.

Data for all employees at the firm shows that average hourly earnings are 12.8% higher for men, while average bonus pay is 18% more than women.

The firm has stated that despite the fact these results are better than the UK national average, it will continue to take action to improve the figures.

Elsewhere, Charles Russell Speechlys has also released its pay gap figures, highlighting a bonus pay gap of 50% between male and female employees, although slightly more women (41%) received a bonus than men (39%).

The mean gender pay gap for hourly pay between male and female employees at the firm is 22%.

Other law firms to have reported their gender pay gap figures so far include CMS, Shoosmiths, Herbert Smith Freehills, Pinsent Masons, Bird & Bird and Taylor Wessing.