A high-profile sex discrimination case involving the multi-million pound bonuses paid to some City financiers has come back to haunt London investment bank Investec.
By Virginia Eastman
BBC business reporter
In September 2002, a tribunal turned down former Investec stock analyst Louise Barton's claim of discrimimation over the fact that her male colleagues were paid more more than her.
But an appeal on Thursday means the case will have to be played over again.
"It's a blow against secrecy in the City," Ms Barton said.
Ms Barton's dispute with Investec dates back to December 2000, when - after seven years at the company - she found herself in dispute with her employers.
Two of her colleagues, she claimed, had been unfairly remunerated for their efforts in sales and research despite being less experienced and more recently employed.
When she asked her employer for assurances that she would not be paid less the company refused to do so, triggering her decision to take them on.
But the original tribunal backed Investec's view that it was entirely within its rights to pay Mike Savage and Mathew Horsmann a higher base salary and a bigger bonus, saying it could not rule on the City's notoriously secretive bonus system.
Still, the Government's Equal Pay Act states that pay between men and women doing the same job must be equal and transparent.
And an EU directive from October 2001 maintains that in matters of sex discrimination over pay the onus is on the employer to prove itself free of discrimination, not the other way round.
The case is not over yet and could still go against Louise Barton.
But the overturning of the original tribunal judgement on points of law will send a sign to the City that the secretive bonus system must be overhauled.
Today the Equal Opportunities Commission, who supported her appeal, said: "No tribunal should be seen to condone a City bonus culture involving secrecy and/or lack of transparency because of the potentially large amounts involved, as a reason for avoiding equal pay obligations."
For its part, Investec says: "Whilst it is regrettable that we will have to resit the original hearing, we have proved once before that we did not discriminate against Louise Barton on the basis of her gender and we are confident that we can prove it a second time."
It will be up to the next tribunal to decide whether or not Louise Barton's case is ruled in her favour.
But over 54% of employment tribunals about equal pay settle out of court and this must now be more likely than it was.