Dr Stephen Jones, who taught religious education and became "assistant deputy headmaster" at St Columba’s College, St Albans, from 2002 until his dismissal for gross misconduct in 2015.
The panel found that Dr Jones failed to maintain proper professional boundaries and allowed an inappropriate relationship with Pupil A that amounted to the teacher acting as though a "third parent".
He went on holiday to Italy with Pupil A and his family in 2014 without informing the school, to Canada later the same year – where he spent five days alone with the pupil – and to Ireland the following year, when he and Pupil A travelled back alone.
Dr Jones was also found to have given expensive gifts to Pupil A, had telephone and text message contact with him, and to have taken him on trips that the pupil had deceived his parents into believing were official school activities. He was also found to have shared a hotel room with Pupil A.
The panel said it “went to great lengths to understand Dr Jones’ motivations in carrying out the actions”, but concluded that while he had in some respects been dishonest, he was not sexually motivated on the balance of probabilities.
Its ruling said: “In his actions, Dr Jones displayed a flagrant disregard for the policies of the college. The panel further found Dr Jones’ behaviour to be indicative of self-propagated exceptionalism. The panel finds that such behaviour is not one which can be tolerated in the profession.
“Whilst the teaching profession is and remains a broad church where differing pedagogies can coexist, this is in part achieved through a universal acknowledgement that, regardless of the methodology adopted by the teacher, the appropriate boundaries in teacher-pupil relationships are respected at all times."
The panel said Dr Jones had shown no insight into his actions since his dismissal and these “amount to a complete failure of professional integrity”.