A long-serving employee of John Fredriksen's Frontline Management has claimed she was wrongfully dismissed — in a lawsuit that lifts the lid on management practices and behind-the-scenes drama.

Sophia Ronaas, 61, served for more than 20 years inside Fredriksen's Oslo stronghold until she was fired in June last year. Robert Hvide Macleod, then chief executive, blamed her for leaking confidential information and for failing to prevent an alleged embezzlement.