As a child, anyone throwing the “your mum” refrain as the ultimate diss did so knowing a fight would surely ensue. It was the verbal equivalent of walking up to someone and spitting in their face – an assault. A put-down utilised by the pathetically stupid, it’s universally accepted as beyond the pale even for the most heated of arguments. Quite how then 54-year-old teacher Michael Rankin thought it acceptable to frequently lob “I shagged your mum” jibes at his students, some of whom were as young as 12, is beyond me. Banter with your pupils is one thing; any abuse of your very real power is another.

The case does highlight questions around boundaries between teachers and their students. How do we navigate the tricky lines between being professionals acting in loco parentis and individuals with personality, desperate to engage nonplussed kids? When can playful banter veer into outright bullying (a domain Rankin had surely crashed into)?

A guiding principle should be remembering that power centres the relationship. The teacher in the room is first and foremost an authority figure. Joking with a child is fine, but teachers are not mates. Believing that you can be a friend while remaining an effective practitioner is a trap. Many fall here and find it hard to regain any sense of control. Rather than this being about the ego of the teacher, it is about the real harm it does to the students. If your teacher is too busy being a mate then they’re not really able to teach you. At the same time, ignoring the needs of pupils by not engaging them in ways that are meaningful and exciting is another dereliction of our duty as educators. Lightening up now and again is essential to keeping your students with you.

No one likes a bore, least of all adolescents tied to their desks 30 minutes before a lunch break. Students do not enter the classroom with an existential take on boredom as a state integral to their becoming fulfilled adults. This is as it should be. Yet no teacher can ensure that all pupils are fully engaged all of the time. If you watched Cirque du Soleil for four hours a week, 39 weeks of the year, year in year out, chances are you’d find yourself yawning in places.

A positive working relationship between teachers and their students doesn’t have to be an all-singing all-dancing act. Being lacklustre isn’t an option either. We only have to look to the world of Westminster to understand that a precise delivery devoid of any hints that the speaker is human does not make one an interesting or motivating educator. Bridging the gap between teachers and pupils by bringing some of who we are as individuals into our teaching is important. It humanises. Teachers become less like automatons intent on draining the joy out of life, and more like people. For me, that might mean injecting my language with informal phrases and constructions so that difficult concepts and ideas can be rendered accessible. I might use slang to poke fun at myself. I might even engage in discussions about who should or shouldn’t have made it to the finals of The Voice. Whatever it is, showing myself as a figure in authority who is nevertheless approachable is something students welcome. It can become a teacher’s most useful behaviour management technique.

Banter and informality are fine, but without the sensitivity to pick up on what an individual or class finds acceptable, it could result in hurt feelings and nursed grudges. Above all, it is about recognising that it is part of the teacher’s repertoire, there to keep students switched on. Our power as teachers means nothing without accepting that we are accountable to our pupils. Great banter without the hard work of showing students dedication to your role as their teacher will look like the gimmick it is. If your lessons aren’t well planned, if there is never any fun, if you haven’t taken the time to get to know them as individuals, then no amount of telling them their haircut is on fleek will help you.