Tennis star Martina Navratilova has claimed she gets paid a mere tenth of John McEnroe's salary for her work as a commentator at Wimbledon.

Speaking on BBC Panorama, the Czech tennis champion—who's considered among the best female tennis players of all time— revealed that she gets paid about £15K ($21K) for her role as a Wimbledon commentator, while John McEnroe earns £150K ($209K) for the same work.

Navratilova said it was "a shock" to discover the difference in earnings. "Unless John McEnroe's doing a whole bunch of stuff outside Wimbledon, he's getting at least ten times as much money than I am for very comparable work," Navratilova said.

She said that if it's happening to her, then other women at the BBC are likely experiencing the same thing on a long-term level. "If this happens to me, and for me it's a part-time job, it's two weeks of my life, but for the women that work there full-time, maybe the discrepancy's not that large, but it adds up over a lifetime, it adds up to an amazing amount of money," she continued.

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During the Panorama interview, Navratilova was asked whether McEnroe "does more hours", or if he's "on air longer."

"Ten times as much? I don't think so," Navratilova replied.

Panorama estimates that McEnroe made "about three times as many appearances" as Navratilova during the 2017 Wimbledon coverage.

In a statement emailed to Mashable, a spokesperson for the BBC said "John and Martina perform different roles in the team" and that McEnroe's role is "of a different scale, scope and time commitment." "They are simply not comparable," the spokesperson said.

In the statement, the BBC said Navratilova is "one of a number of occasional contributors who is contracted to carry out a fixed volume of work and paid per appearance."

The BBC believes her pay reflects what she is asked to do, her time commitment, her level of broadcast experience, profile and track record and expertise. At Wimbledon 2017 her work amounted to 3 live match commentaries, 4 highlights appearances, 1 short video and 2 other short studio appearances. Beyond this she has no contractual commitment to the BBC.

The BBC said its contract with McEnroe is "entirely different" and that he is "regarded as the face of our Wimbledon coverage."

"John is contracted to be on call for the BBC across the entire 13 days of the tournament, subject to a commitment with one US broadcaster, and is on air every day.

He worked on live match commentaries on 12 of the 13 days along with highlights programmes, opening links, regular studio pieces with Sue Barker, studio analysis, filmed sequences and 6-0-6 programmes for BBC Radio 5 live, as well as publicity work.

The BBC added that McEnroe is "widely considered to be the best expert/commentator in the sport, highly valued by our audiences."

"His pay reflects all of this; gender isn’t a factor," the BBC concluded.

This isn't the first time the BBC has found itself embroiled in an equal pay dispute. In January 2018, the BBC's China Editor Carrie Gracie resigned from her post after learning she was earning 50 percent less than her male counterparts for the same work. In a powerful open letter, she accused the BBC of "breaking equality law" and called on the public broadcaster to "value men and women equally."

During the Panorama interview, Navratilova said the discrepancy is "extremely unfair" and makes her "angry for the other women that go through this."