Kresh Ramanah, 40, had an affair with one student and told another she would fail her exams unless she slept with him, the tribunal heard.
Mr Ramanah, personal tutor to the all-female class at Wealdon College in east Surrey, told the young women "I can imagine you all sitting there naked", the tribunal was told.
Mr Ramanah, married to a woman he met while she was a student nurse, frequently visited Sarah Radlett in the nurses' home and took her on holiday to Paris but mounted a campaign of harassment against her when she ended their affair.
He told her he would make her fail her exams if she did not stay with him and when she did in fact fail her second-year exams he said to her: "I am very pleased to tell you, you have," it was alleged.
The scandal came to light when Linda Archer, manager of the 240-pupil nursing college, held a course evaluation session with Mr Ramanah's class after they finished their training.
She told Croydon Industrial Tribunal: "One or two of them said things to me that I found most disturbing. Sarah Radlett started the discussion. They voiced things to me like 'We have not complained until now because we knew Mr Ramanah could affect our exam results.' They perceived he had enormous influence over everybody at the college including me.
"Sarah started off the discussion by saying Mr Ramanah had once said to her 'If you don't sleep with me, you will fail your exams'."
Mr Ramanah was dismissed from his post in 1993 for gross misconduct. He denies all the allegations and is claiming unfair dismissal and racial discrimination.
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