An employment tribunal found that Dawn Bailey, 52, was unfairly dismissed from her role as PA to the Chief Executive of Lockheed Martin, one of the world’s largest defence companies, after she developed depression and a chronic illness which left her short of breath and excessively tired.

Stephen Ball, the 59-year-old CEO of the UK defence firm, announced a few days after her 50th birthday that it was “time for a younger team”.

Miss Bailey had a 19 year unblemished career with Lockheed Martin, but resigned in February 2012 after it became impossible for her to stay.

An employment tribunal found that Miss Bailey had been wrongfully dismissed from her post and as a result of her illness had been unfavourably treated.

The tribunal accepted that Mr Ball had made the comment about wanting a “younger model” but considered that it was a joke rather than a discriminatory remark, and rejected her claim for age discrimination.

However because she had been unfairly treated as a result of her illness, this was equivalent to a “disability”.

Miss Bailey had taken several weeks off work in 2011, and in her absence found that her job had been altered and sidelined, and the tribunal agreed that she had been “marginalised” on her return to work after she took time off. It was found she was met with “cold-shouldering” as opposed to sympathy and support from her colleagues and management. Miss Bailey accused her employer of “intolerance of illness and seniority” after he repeatedly referred to her age. In December 2011 she was suspended on “management directed leave” and was escorted fromthe premises; she resigned three months later.

Miss Bailey is considering appealing the ruling because the tribunal did not uphold her age discrimination complaint. The tribunal stated “We were not persuaded that Mr Ball had generally had an antipathy towards the claimant because of her age.”