Samira Ahmed has won her equal pay claim against the BBC in a landmark case that lawyers say could leave the broadcaster facing a bill running into the millions for similar claims by other female staff.

Ahmed, the presenter of viewer feedback programme Newswatch, claimed she was owed almost £700,000 in back pay because of the difference between her £440-an-episode rate and the £3,000 an episode Jeremy Vine received for hosting the similar Points of View programme.

An employment tribunal unanimously concluded that the BBC had failed to provide convincing evidence that the pay gap was for reasons other than gender discrimination, although the BBC continues to dispute this.

Ahmed said she was glad the case was resolved after years of dispute with the broadcaster. She said: “I love working for the BBC. No woman wants to have to take action against their own employer.”

The National Union of Journalists’ general secretary, Michelle Stanistreet, who backed Ahmed’s case, said there were about 20 other cases involving claims of unequal pay at the BBC heading to tribunal, while another 70 cases remained unresolved.

But she said BBC executives had shown a new willingness to resolve outstanding cases after Ahmed’s tribunal. Stanistreet said: “Since the hearing I met with the BBC and I pressed them to use this window of opportunity to think: ‘Actually we need to put effort into resolving these outstanding cases, not putting ourselves through the self-harm of another tribunal like Samira’s.’ Some of them have already been satisfactorily resolved. But there are still more to sort out.”

The 40-page tribunal judgment was damning of the broadcaster’s argument that Ahmed’s job as presenter of Newswatch was significantly different to Vine’s as a presenter of Points of View.

They dismissed the BBC’s argument that Points of View required a “cheeky” presenter such as Vine with a “glint in the eye”, concluding that there were only “minor differences” in the work the two presenters did presenting the two comparable programmes.

In a withering assessment, they wrote: “Jeremy Vine read the script from the autocue. He read it in the tone in which it was written. If it told him to roll his eyes, he did. It did not require any particular skill or experience to do that.”

The report from Judge Harjit Grewal and the panel members Mr S Godecharle and Mr P Secher concluded that under the Equality Act the BBC “has not shown that the difference in pay was because of a material factor which did not involve subjecting [Ahmed] to sex discrimination”.

The judgment did not specify whether Ahmed would receive the hundreds of thousands of pounds she had claimed in backpay as a result of the discrepancy. The BBC has the option to appeal but a spokesperson said the corporation was still considering the implications. If it declines to appeal against the verdict the BBC could face an enormous legal bill, substantial costs, and potentially other large settlements with female BBC staff bringing equal pay cases.

During the tribunal the BBC defended paying Vine substantially more than Ahmed, saying that while Newswatch required a news journalist, he was a light entertainment presenter who “would often dress up for small visual gags”. Ahmed’s legal team argued this was incorrect, as he was only known to have worn “one wig and one hat” and the jobs were in effect the same.

The judges said: “We have difficulty in understanding what [the BBC] meant by a ‘glint in the eye’ and how that translated into a ‘skill’ or ‘experience’ for the job. How does one acquire such a skill or experience? In any event, the lighthearted tone and any cheekiness were achieved primarily by the script being written in a particular style. The attempts at humour came from the script.”

They also dismissed the case that Vine’s £3,000-an-episode fee was the market rate for such a high-profile star. “The evidence indicates the contrary: that Jeremy Vine was paid above the market rate payable for him for Points of View.”

Lawyers warned that the financial implications of this case could be huge. Caroline Underhill of Thompsons Solicitors, who represented Ahmed, said: “The ball is now in the BBC’s court: they need to heed the lessons from this judgment and engage in meaningful negotiations with the NUJ to ensure genuine pay transparency, and pay equality, for all employees. Today’s judgment helpfully clarifies some of the fault lines in the BBC’s pay structure that can – taking into account the facts of each individual case - be used to support or advance other potential claims against them.”

High-profile presenters and campaigners hailed the decision and praised Ahmed, with the BBC host Carrie Gracie – who resigned over equal pay in 2018 – expressing her pride in Ahmed. “As for BBC bosses, time to stop digging,” she said.

The BBC Radio 4 presenter Jane Garvey also praised Ahmed, tweeting: “Just brilliant … it took real courage and she has it.”

Polly Rodway, a partner at the law firm BDBF, said: “There is a big floodgates argument here, so the ramifications of the judgment for the BBC will be significant as lots of other claimants will now pursue the BBC and, economically, they could end up paying a lot more in light of this judgment.

“We are talking about potentially many more claimants … I am not sure I can put a number on it but the costs could be millions.”

The BBC emphasised that the verdict was based on tribunal judges failing to be convinced by the evidence put forward to justify the difference in pay on grounds other than gender. For instance, the judges were not convinced by the quality of the BBC’s evidence that Vine was especially popular when he was offered £3,000 a show in 2008.

Although the corporation is still considering the verdict, the BBC does not see it as a blanket ruling affecting all news and entertainment staff, suggesting it could still fight other pay tribunal cases and it does not necessarily believe this sets a broader precedent.

Forcing open pay disclosure on the BBC has had a significant effect on rates for women, with many female staff receiving increases since figures for leading staff were first revealed in 2017.

Vine’s role presenting Points of View helped the BBC with its obligation to keep his salary high, fulfilling a requirement of a broader pay deal agreed in 2008, which was designed to keep one of the broadcaster’s biggest stars from jumping ship to a commercial rival.

During the tribunal the BBC played down the audience for its own rolling news channel, arguing Ahmed’s programme was made for the “relatively niche” service so should not be considered in the same league as Points of View, which was on BBC One. In addition, an unredacted list of more than 100 women who had brought equal pay cases was also made public in an inadvertent data breach, prompting complaints to the information commissioner by those who did not want their names made public.

A BBC spokesperson said: “We’ll need to consider this judgment carefully. We know tribunals are never a pleasant experience for anyone involved. We want to work together with Samira to move on in a positive way.”