You say that this relationship started three years ago, when the former pupil was under 18, and that the reason the teacher has now told you about it is that they are about to move in together. You won't need me to tell you that this man may have committed a crime under the Sexual Offences Act 2003, and you undoubtedly will have sought legal advice about your position.
Assuming that you feel this leaves you some wiggle room, what are the facts? A (presumably) young male teacher started a relationship with a sixth-former. This isn't so unusual. One estimate is that there are at least 1,500 such affairs a year in the UK. Neither is it uncommon for such relationships to last. I know of two marriages that began this way. But anything you do must be based on your knowledge of the people concerned. If you believe that this teacher is an honest man who, blinded by love, made a single error of judgement three years ago, and if you believe that the young woman is not the type to go stirring up trouble should the relationship turn sour (although, of course, who knows?), then there's much to be said for doing nothing. The relationship must be old news by now around the school community and, as you say, good maths teachers are like gold dust.
Of course, this means that any future accusations about this affair, or any new sexual scandal, will put you in a very difficult position. It may be easier to suggest that the teacher move on.
Make a note of the conversation, suspend him, inform the chair of governors and call the police. He has told you about a crime that he has committed. If you ignore his confession, all the children in the school will know, as will the staff. You will be sending a message that sexual relations between staff and pupils are OK by you.
I went to such a school in the liberal 1960s. A very good English teacher, adored by pupils, had sexual relations with at least one boy and one prepubescent girl. He lost interest in the girl when she went through puberty, and about 10 years later she killed herself. She was one of my best friends.
Sally Eva, London, SE15
Any sexual contact between pupils and teachers is a violent abuse of trust, and lets down everybody in a school. My brother taught at a prep school where, for years, the head secretly abused girl pupils. No one knew, but everyone felt tainted by what this man had done when it came out in court. I believe you must sack this teacher and report the full circumstances to the police.
Caroline Levett, East Sussex
I had a relationship like this when I was 23 and teaching history at a sixth-form college. I'm not proud of it, but my point is that, these days, girls of 17 are adult young women who know what they want and can be unbelievably precocious. If they set their sights on you, it can be almost impossible for any teacher to resist.
Name and address withheld
Next Week's Quandary
Dear Hilary, Help! Does anyone know anything at all about how to get reluctant teenage girls moving? I am a PE teacher working in a challenging school who has tried everything – yoga, jazz dance, the lot. A few of my girls sometimes get enthused, but about 40 per cent refuse to even try.
Send your replies, or any quandaries you would like to have addressed in this column, to h.wilce@ btinternet. com. Please include your postal address on your message. Readers whose replies are printed will receive a Collins Paperback English Dictionary 5th Edition. Previous quandaries can be found on www.hilarywilce.com, where they can be searched by topic
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies