A secondary school teacher who claimed he had consensual sex with a 16-year-old student has been struck off the register of teachers by the High Court.

The teacher, who was in his 50s at the time of the incident, made the claim about the interaction to gardaí even though the pupil was under the age of consent and intoxicated at the time.

High Court president David Barniville on Monday approved the sanction sought by the Teaching Council, striking the teacher off its register and prohibiting him from being restored to it for a 30-year period.

The judge said the “incredibly serious” sanction in the case was “well merited” given the teacher’s professional misconduct was of the most serious kind.

The teacher cannot be named to protect the identity of the pupil. The teacher taught at the pupil’s school.

Barrister Eoghan O’Sullivan, for the council, said his client relied on admissions made by the teacher in a cautioned Garda interview in upholding an allegation of professional misconduct against him.

The teacher was arrested and interviewed by gardaí after allegations of rape and sexual exploitation were made against him by the pupil, O’Sullivan said. The teacher consistently denied the allegations.

However, the teacher admitted having what he described as consensual sex with the pupil when she was 16. The court heard the pupil was intoxicated at the time of the incident, which occurred at a property the teacher was staying at.

The teacher was not prosecuted over the matter as the pupil denied that such an incident had occurred, O’Sullivan said.

However, the teacher did face criminal proceedings for other alleged sexual offences. During the trial, the Director of Public Prosecutions entered a nolle prosequi on the charges, Sullivan said.

The council investigated the teacher separately. Arising from his admissions to gardaí regarding his interactions with the girl, the council ultimately concluded that the teacher was guilty of professional misconduct. It was satisfied that the admission was made freely and voluntarily.

In deciding the sanction, the council noted that it was “difficult to contemplate” a more serious example of misconduct.

O’Sullivan said that given the “deplorable” nature of the man’s conduct, the sanction was appropriate.

The judge made the orders, as sought, confirming the sanction. He noted that in its reporting following the inquiry into the case, the council said the teacher displayed a lack of insight and remorse and at times considered himself a victim.