A City lawyer suing her former bosses for £19 million was using an alternative personality when she successfully interviewed for another job while suffering from a serious mental illness, an employment tribunal was told yesterday.

Gill Switalksi, 51, former head of legal affairs at Foreign & Colonial (F&C), was able to convince a senior executive at a rival asset manager that she was “full of energy and drive” despite her poor mental health, an expert witness said.

Steven Hirsch, a consultant in adult psychiatry, said that there was “nothing sinister” about Ms Switalski giving a strong performance at the morning interview and then displaying signs of being “withdrawn” to a psychiatrist the same afternoon.

Ms Switalski experienced a psychological condition called dissociation, Professor Hirsch said, where individuals can push aside negative feelings.

“Dissociation is not a matter of putting on a brave face . . . you tap into a different personality,” said Professor Hirsch, who was called as an expert witness by Ms Switalski, as she defends allegations that she faked a nervous breakdown to secure a higher compensation payout from F&C.

On Monday, lawyers for F&C revealed evidence including details of Ms Switalski’s successful interviews, which F&C says proves she is a “very plausible liar” whose past testimony cannot be trusted. F&C is asking the tribunal to reconsider a ruling that said Ms Switalski suffered discrimination and victimisation while at the company. F&C called an expert witness, Professor Simon Wessely, of King’s College London, who said there was “some debate about whether dissociation exists” and that it would be impossible for an interviewer not to notice “something very strange happening”.

The tribunal will now consider whether to order a retrial.

Explore Law

• Columnists

• Law Panel

• Law Reports

• Student Law

Times Recommends

• The best legal yarns this Christmas
• Legal school 'earned £1m by exploiting bar course'
• Axe may fall on 5,000 more City lawyers