Travers Smith has lost a discrimination case brought against it by a former trainee who claimed she was denied a permanent role at the firm after becoming pregnant during her final seat.

Katie Tantum instructed law firm Leigh Day to launch the case in February after failing to gain a newly-qualified position in Travers' real estate department.

Last Thursday (16 May) the Central London Employment Tribunal found that Travers' evidence relating to the discussions concerning Tantum's qualification was "implausible".

According to the judgment, Travers head of real estate Julian Bass and litigator Andrew King, making the decision over how many positions to fill, were "prepared to discriminate because of pregnancy".

The ruling stated: "Mr Bass was aware of the pregnancy of the claimant when he contrived the reduction of the second post. We conclude that the reduction of the second post was a device to prevent the claimant from being offered the post of newly qualified solicitor in the real estate department."

The tribunal recommended that Travers partners and senior staff "should participate in discrimination training" and there should be formal documentation to ensure a transparent process in deciding which trainees get positions, with feedback for those who are unsucessful .

A Travers spokesman said: "We really did not expect this decision at all. We are very surprised and disappointed by it. Throughout the proceedings, we thought our evidence was strong. We still believe that, although the employment tribunal has found otherwise on one aspect of this claim.

"Before we took the decision to defend this case, we reviewed the allegations against us extremely thoroughly with everyone involved, including Andrew King and Julian Bass, as well as counsel. If we had not been satisfied with the strength of our defence, we would not have fought the claim.

"We have complete confidence in the integrity and professionalism of Andrew and Julian, built up over their many years at the firm. None of our discussions with either of them in relation to any aspect of this case has changed that.

"We sincerely regret that one of our former trainees was left unhappy from her experience at the firm, and we will take on board the lessons to be learned. Our trainees, associates and all our staff are fundamental to the future of the firm, and we are determined to do everything we can to ensure that they are all happy here.

"Our commitment to diversity takes many forms and will remain unwavering. We are, for example, founding signatories of the Law Society's diversity and inclusion charter, and proud to be members of Stonewall's Diversity Champions Programme. Some 10% of our associates, and four of our female partners, have flexible working arrangements. The tribunal decision strengthens our resolve to ensure that this commitment to diversity is properly understood. We have for some time operated a rolling programme of discrimination training within the firm. This will continue and we will be taking the opportunity to review the transparency of our approach to trainee qualification at the firm too."

Leigh Day employment barrister Elizabeth George, who represented Tantum, said: "It takes courage and tremendous resilience to stand up to your employer, even more so when that employer is a leading City law firm and you are only just embarking on your legal career. All of the witnesses at the tribunal on behalf of Travers Smith were senior partners in that firm.

"The evidence in this case was very clear: Katie's level of performance meant that she would have been offered a permanent role at Travers Smith but she was denied that role because she was pregnant."

David Massarella of Cloisters was instructed by Leigh & Day, while Travers turned to Essex Court Chambers' Edward Brown.

A remedies hearing will take place on 5 June.