Malcolm Smith, a former maths teacher at The Snaith School in East Yorkshire, sent personal text messages to Pupil A between September and October 2017, and also allowed her to use his mobile phone to call her mother, a professional conduct hearing of the Teaching Regulation Agency (TRA) heard.
In a witness statement, Pupil A said Mr Smith had text her when she was off school ill, asking her if she was OK. She said this had made her feel "weird". The panel also saw evidence of other texts between the pair.
Mr Smith said he had received a text message from Pupil A and responded to her about educational issues, but accepted he shouldn't have engaged with her.
He said that he had allowed her to use his phone on the day in question after a fellow pupil had been found hanged and emotions were "running high". Mr Smith accepted that he ought to have directed her to use the school phone rather than his own.
The panel heard how he drove Pupil B home from her work experience in September 2017, and also hugged her when she returned from the placement.
Mr Smith explained that Pupil B's mother was reluctant to travel to Hull to collect her daughter, and so, as he was attending the placement anyway, he offered to collect the student. He said his motivation was that he was "just trying to help out".
He said Pupil B had hugged him after she had done well on results day and that he responded in a "wooden way". Mr Smith stated he regretted what he had done but deemed it a "minor event".
He is also alleged to have exchanged USB sticks which they had uploaded music to with Pupil B in October 2017 and told her how he was subject to an interim suspension due to an allegation made by another pupil that he had inappropriately touched them.
In relation to the music allegation, Mr Smith said he was trying to help and support a pupil who was finding life difficult, but accepted that he had crossed professional boundaries.
In relation to the interim suspension, he said he had previously received a call from Pupil B's mother, who had heard somehow about the allegation, expressing her support for Mr Smith and had asked to know how it went. It was in this context that the conversation with Pupil B took place. Mr Smith accepted that he had been told by the school not to discuss this with anyone, but said he felt "isolated and unsupported".
The professional conduct panel also heard how he referred to Pupil B by a nickname in text messages sent to her mother, and despite having received a text from Pupil B's mother instructing him not to have any contact with her daughter, approached her asking how long she planned to avoid him for.
Despite receiving management advice to only speak to Pupil B during lesson time, Mr Smith approached her in a corridor and discussed applying for a job at the sixth form college where she would be attending.
The panel also heard how Mr Smith sent text messages containing derogatory remarks about Pupil A to Pupil B's mother in November and December 2017.
One of the messages read: "The knife in the back from the mad... didn't do too much damage", while another stated: "(Pupil A's) lies have won, that she seems to have set out to stick a knife in both (Pupil B) and myself".
The panel stated: "Some of the above conduct took place after Mr Smith had on October 6, 2017, been spoken to by his employer about expectations of the Code of Conduct for Staff Policy and about what is deemed to be inappropriate and unprofessional communication."
Mr Smith admitted unacceptable professional conduct.
He resigned from his teaching post in April 2018 after working at the school since September 2006.
The TRA refrained from imposing any further sanctions on Mr Smith.
It said: “The fact that Mr Smith has been subject to both the School's disciplinary process and the TRA proceedings, is likely to have acted as a salutary and sobering lesson to Mr Smith such that the repetition of similar conduct is unlikely.
“Given that the nature and severity of the behaviour were at the less serious end of the possible spectrum and, having considered the mitigating factors that were present, insight and the low risk of repetition, the panel determined that a recommendation for a prohibition order would not be proportionate in the circumstances of the current case.”
The Snaith School Headteacher Michaela Blackledge said: "When we became aware of the issue we referred the matter to the Teaching Regulation Agency. Having read the report we accept and agree with the findings and the matter is now closed.