Charterhouse teacher arrested on suspicion of raping former pupil A spokesman for Surrey Police said: "A 48-year-old man is currently on conditional bail in relation to an allegation of a serious sexual offence at an address in Godalming. He is due to report back to Guildford Police Station on 16 July 2013. A police source confirmed that the "serious sexual offence allegation" was rape. A Charterhouse spokeswoman said: "We can confirm that a teacher has resigned from the school following serious concerns regarding allegations of inappropriate behaviour. It would be improper to say anything further. Parents say they were told this week that Dr Johnson has resigned because of "an inappropriate relationship." The letter from headmaster Rev John Witheridge makes no references to the arrest. It reads: "I write to inform you that Dr. Dean Johnson (Physics) has resigned after the school was made aware of serious concerns about the existence of an inappropriate relationship with a former sixth-form girl. I am sure you will understand that I am unable to go into any further detail. Arrangements are being made to cover Dean's teaching and other duties. If you have any concerns, do please let me know, and I will do my best to answer them if I can. Dr Johnson appears to have advertised himself as a private tutor, charging between £25 and £40 an hour for lessons in Physics, Astronomy and Astrophysics to GCSE, A-level and university standard. On the 'A+ Tutors' website for the Surrey area an entry in his name says: "Physics Master at Charterhouse school for 12 years, Oxford and Cambridge graduate in Astrophysics. I am one of the best Physics tutors you will ever get! Charterhouse is 400 years old and is recognised as one of the most successful schools in Britain. It is predominantly a boarding school with around 800 pupils, taking boys from 13 and girls in the Sixth Form.