One of the BBC's most experienced journalists has quit her post, accusing the corporation of running a "secretive and illegal" pay structure.
In an open letter which begins "Dear BBC Audience", China editor Carrie Gracie says licence fee payers have a right to know the corporation is not "living up to its stated values of trust, honesty and accountability".
Gracie claims to have discovered that male international news editors were being paid 50% more than women in the same role.
She writes: "I am not asking for more money. I believe I am very well paid already – especially as someone working for a publicly funded organisation. I simply want the BBC to abide by the law and value men and women equally."
Based in China, Gracie says she was offered a "big pay rise" when she raised the issue but that it was still less than men in the same role.
She claims that managers explained the disparity as being down to "differences between roles".
"I have been subjected to a dismayingly incompetent and undermining grievance process which still has no outcome," writes the journalist.
Gracie – who revealed live on air in 2009 that she was paid £92,000 – says she intends to return to her former job in the BBC's TV newsroom "where I expect to be paid equally".
It revealed disparities between some presenters in similar roles – for example a £200,000 gap between Huw Edwards and Fiona Bruce, who both present evening news programmes.
Director general Tony Hall said at the time the BBC needed "to go further and faster on issues of gender and diversity".
Gracie's letter claims many staff have since been negotiating internally for equal pay "but managers still deny there is a problem".
She warns: "This bunker mentality is likely to end in a disastrous legal defeat for the BBC and an exodus of female talent at every level."
Responding Gracie's claim, the BBC said: "Fairness in pay is vital. A significant number of organisations have now published their gender pay figures showing that we are performing considerably better than many and are well below the national average.
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"Alongside that, we have already conducted a independent judge led audit of pay for rank and file staff which showed 'no systemic discrimination against women'.
"A separate report for on air staff will be published in the not too distant future."