The BBC is facing at least a dozen legal cases from female members of staff who believe they were illegally paid less than their male counterparts, as a high-profile employment tribunal hearing gets underway involving the presenter Samira Ahmed.

Ahmed is claiming she was underpaid by hundreds of thousands of pounds since taking over as host of the BBC’s Newswatch programme in 2012.

On Monday she arrived at the central London employment tribunal accompanied by dozens of well-wishers, including BBC Breakfast show host Naga Munchetty and the poet Lemn Sissay, who cheered as Ahmed entered the building.

Carrie Gracie, the BBC’s former China editor who resigned last year over equal pay, told reporters at the tribunal hearing that Ahmed is only the first of many cases in the pipeline: “Women want equality, they want their work respected. They don’t want their work to be undervalued. It affects everything about their lives, it’s not just about finances which are important … it is also about self-respect and about progression as well as pay.”

Gracie said that women such as Ahmed were willing to risk damage to their career in order to see “equality honoured” after being unsatisfied with the BBC’s internal pay review processes: “Her case is emblematic and extremely important to all the other women still fighting.”

Equal pay is different to the broader issue of the gender pay gap. Cases brought under equal pay legislation are based on specific claims that an individual was paid less than a colleague for doing the same, or equivalent, work.

Gracie also highlighted wider concerns about BBC executives being unwilling to accept they have made mistakes, citing the recent row over the handling of a complaint against Naga Munchetty regarding comments about Donald Trump: “This is not the kind of thing that management likes to see. None of these people are going to be the favourites of their management while doing this.”

Related: Samira Ahmed takes BBC to court over claim of unequal pay

The BBC has already accepted that Ahmed was underpaid by between 50% and 33% compared to male colleagues for her work on programmes for Radio 4 and Radio 3, pledging to make up the difference.

However, they are resisting Ahmed’s claim that she was unfairly paid for her work presenting Newswatch , for which she received £440 an episode. She claims this is unfair because at the same time Jeremy Vine was paid £3,000 for presenting each episode of Points of View, a programme of similar length also featuring viewer feedback on BBC programmes. Calculations suggest the total claim for five years of systematic underpayment could be as much as half a million pounds.

Ahmed’s tribunal hearing was closed to the public and reporters, as her representatives argued with BBC lawyers over whether to redact certain material.

According to an individual with knowledge of the case, the judge ordered the BBC to disclose internal documents relevant to the case. As a result witnesses will only start giving evidence on Wednesday in hearings that could be potentially embarrassing for the broadcaster and lay bare some of its pay discussions.

Before entering the hearing Ahmed, who is fighting the case with the support of the National Union of Journalists, issued a statement insisting she continued to believe in the BBC’s mission.

“I have a sense of pride working for a public service broadcaster which seeks to represent the diversity of Britain and its licence-fee payers. On the back of my BBC ID card are written the BBC values, which include ‘we respect each other and celebrate our diversity’ and ‘we take pride in delivering quality and value for money’,” she said.

“I just ask why the BBC thinks I am worth only a sixth of the value of the work of a man for doing a very similar job.”

A BBC spokesperson said: “Points of View is an entertainment programme with a long history and is a household name with the public. Newswatch – while an important programme – isn’t. Samira was paid the same as her male predecessor when she began presenting Newswatch. Gender has not been a factor in levels of pay for Points of View. News and entertainment are very different markets and pay across the media industry reflects this.”