Ann Francke, chief executive of the Chartered Management Institute (CMI), which conducted the research with XpertHR, said: "Too many businesses are like 'glass pyramids' with women holding the majority of lower-paid junior roles and far fewer reaching the top.
"However, the picture is worst at the top, with male chief executives cashing in bonuses six times larger than their female counterparts."
The scale of the gender pay gap
There's no doubt about it. The average man is paid a lot more for doing exactly the same work as a woman.
The government wants to turn the tide by forcing large companies to provide details of how much they pay their employees - both male and female.
Businesses are dragging their feet when it comes to reporting these figures, though. As of 22nd September, just 77 out of 7,850 eligible employers have fulfilled their reporting obligations.
Among those who have released data, the shocking news is that the pay gap is even worse than believed.
For people in management roles, for example, analysis last year put the gap at 23.1%, or £8,964.
However, greater access to salary information has allowed researchers this year to show the gap actually stands at 23.6%, or £9,326, when judged on basic salary alone.
And once bonuses, perks and commissions are taken into account, the figures show women missing out to the tune of £11,606 a year, a pay gap of 26.8%.
As you move up the corporate ladder, things get even more unfair. The average bonus for a male chief executive is £89,230, or a stonking 83% more than the £14,945 a female chief executive typically receives.
XpertHR's Mark Crail said: "Some people have tried to explain the gender pay gap away as being the result of different working hours or individual career choices. But it is clear that the pay gap is a very real fact of life."
How to fight back
You don't have to accept that you will be paid less for being a woman. Here are three ways to fight back against the gender pay gap.
Bite the bullet and ask for a rise
One - although far from the only - reason men are paid more than women is that they tend to be more proactive about demanding higher salaries.
So if you think you deserve to be paid more, ask for it.
You can increase your chances of success by coming up with all the reasons you deserve more money, researching how much people in similar roles are earning, and picking your moment.
There's little point asking for a rise if you know your company is going through a bad time, for example.
Claim all your perks
It can be tricky asking for a pay rise. But these latest figures suggest that much of the pay gap is made up of perks such as commission and company cars.
And the good news is: asking for extra perks is often easier than demanding an increase in your salary.
Check out what perks are available, choose the ones that are worth the most to you and then ask to see your boss.
Look for a new job
Finding a new job with a higher salary is a surefire way of increasing your income. So if you feel undervalued in your current role, don't be afraid to start looking for a better option.
Just remember to research any prospective employer's pay practices to ensure you don't get fobbed off with a lower salary than men in the same role.
In many cases, it's worth holding out a bit in negotiations, and preparing a list of reasons why you are worth more, to get the pay packet you deserve.