Nathan Rowe, 29, was employed at Lea Manor High School as a senior tutor at the time of the relationship, which began when the girl was still in her early teens.
Although Rowe resigned from Lea Manor in January 2016 after news of the fling came to light, a fitness to practice hearing was heard before the National College of Teaching and Leadership (NCTL) on March 17.
Following the hearing, Rowe was permanently banned from teaching.
NCTL deputy director of regulation Alan Meyrick stated: “The conduct of Mr Rowe fell significantly short of the standards expected of the profession.
“[It] involved a sustained period of inappropriate and sexually motivated contact with [the girl] who was known to be vulnerable.
“There is a strong public interest consideration in the protection of pupils, given the serious finding of an inappropriate relationship with a vulnerable young teenager.”
The hearing was told that on one occasion, Rowe was caught kissing the girl’s neck with his arms around her, and in a separate incident was seen snuggling up to her with his hands on her hips.
Eventually, one of the girl’s friends confided in an adult. The relationship was reported to Bedfordshire Police in October 2015 but no criminal charges were brought.
Nevertheless, private text messages were presented to the NCTL panel. In one message, Rowe texted “I love u tho” after the girl tried to break off contact.
Other messages included kisses, addressing the girl as “babe” and “pretty little thing” and emoticons of blowing hearts and kisses.
In further texts Rowe told the girl, “You look older in that pic!”, “Beautiful till u start a mouth lol” and “Could have just gave u cuddle”.
The panel was also shown suicidal text messages sent from the girl to Rowe, who was criticised for taking no safeguarding actions.
They also had sight of a letter from Rowe who apologised for his behaviour and admitted the allegations, although he had previously denied them when confronted by the school.
The NCTL added: “The panel has seen evidence that suggests that he was previously subject to warnings at the school regarding inappropriate contact with pupils.”
Lea Manor High Scool headteacher Amanda Simpson said: “Safeguarding and promoting the welfare of children is given extremely high priority at Lea Manor High School. We have robust procedures in place and immediately put these in to action as soon as we were made aware of the allegations.
“The employee was immediately removed from the school and subsequently suspended pending the outcome of police and internal investigations.
“Prior to a disciplinary hearing being held by the school in February 2016, Mr Rowe resigned from his post in January 2016. We referred Mr Rowe to the DBS, who subsequently referred him to the National College of Teaching and Leadership.”