Coaxing a class full of truculent teens through their GCSEs can test even the most battle-hardened of teachers. Though it can often be great fun, it can sometimes prove fractious.

It certainly did with Jane.

Difficult and confrontational, I could expect a missing homework and an argument with her in most lessons. Every week was a struggle. All too frequently, her bleak personal life would be laid open like a drawer of knives: she would argue with her so-called friends and then me. Boundaries had to be drawn regardless and her vicious salvos simply had to stop.

Mid-year, Jane left my classroom - and school - for good. My instinctive feeling was one of relief, mingled with guilt at her permanent absence. What could I have done differently? Perhaps if I had only acted earlier, nipped it in the bud before missteps became misdemeanours...

The theory that stamping out the early misbehaviour of Jane could have set her on a different path, one to perfect behaviour and success, is alluring. And it is the very premise that underpins the notion of “zero tolerance”, which appears, anecdotally, to be becoming more popular in the UK. But does it work?

Like a lot of our imports, zero tolerance is American in origin. The very first policies appeared in US schools decades ago, to address issues of serious violence, drugs and, in particular, gun crime.

In the 1990s, the approach was popularised in many US schools and became related to the “broken windows theory” of crime reduction, which was credited for significant crime rate drops across American cities such as New York.

The idea was this: by dealing sternly with minor crimes - mere “broken windows” - serious crimes would in turn be reduced. Hero police chiefs, such as Bill Bratton from New York, heralded their successes. US schools listened and learned.

Significant criticism

A defining characteristic of zero-tolerance approaches is that all students receive penal treatment for all misdemeanours. In their 2008 research, Are zero tolerance policies effective in the schools? (bit.ly/ZTPEffective), the American Psychological Association Zero Tolerance Taskforce outlined the assumption of school leaders: “In theory, zero tolerance deters students from violent or illegal behaviour because the punishment for such a violation is harsh and certain.”

But despite success being heralded in many zero-tolerance US schools, significant criticisms mounted as evidence started to emerge that such behaviour policies led to a disproportionate numbers of ethnic minority students being excluded from schools (bit.ly/ZTExclusions).

And the inflexibility and fallibility of zero tolerance has been writ large now in decades of damning evidence from America, drawing into question whether it is the best solution for our classrooms.

In these systems, students such as Jane too often become depressing social statistics. The relationship between school exclusion, illiteracy, ill health and crime is laid out in stark relief by the Institute for Public Policy Research in their research, Making the difference: Breaking the link between school exclusion and social exclusion (bit.ly/DifferenceReport).

They showed that, “despite only 6,685 reported permanent exclusions last year, 48,000 of the most vulnerable pupils were educated in the alternative provision sector.” Once excluded, students such as Jane were twice as likely to go on to be taught by a non-qualified teacher or a supply teacher.

As exclusions are on a dramatic increase in England (bit.ly/Exclusions300), such evidence matters more than ever.

But there are no easy fixes. Misbehaviour like that shown by Jane simply cannot be condoned in our classrooms. Regardless of the personal prisons that such students may emerge from, it does not excuse her damaging the education of her peers.

And yet, the plain truth is that the students whose behaviour we tolerate the least are the ones that need us the most. Like the scales of justice, we must negotiate a delicate and difficult balancing act.

Early support

The scales are too often tipped against students like Jane. In our role - in loco parentis - we have a responsibility to not cast her off-roll at the first opportunity. As the old saying goes, prevention is better than a cure.

For students such as Jane, getting in early support after a failed test or a missed homework, rather than escalating punishments, can make all the difference. An excellent piece of 2017 US research from the What Works Clearinghouse, Preventing Dropout in Secondary School (bit.ly/PreventDropout), is very helpful in this regard.

They recommend an early prevention approach based on their ABC markers for likely school dropouts such as Jane: A - attendance; B - behaviour; C - course grades. Their focus addresses misbehaviours and promotes firm, high standards, but they also encompass vital related issues, such as how missing school and struggling with accessing the curriculum can make problems worse for students such as Jane.

It advocates an approach that considers context, that is not paint by numbers.

In his 2017 Department for Education pamphlet, Creating a Culture (bit.ly/CaCult), behaviour consultant Tom Bennett extols the importance of school culture and states that it needs to be built “in practice with as much detail and clarity as possible”. He offers a helpful new “three Rs”: “routines, reactions and responses - and relationships”.

We should of course develop routines and habitual responses to misbehaviour, but we must tend to relationships, too. That seems to be what zero-tolerance misses.

The report also gives a good indication as to why we should always be wary of policy tourism: Bennett relates the importance of “contextual factors” and how the “wholesale import of ideas and strategies from alien school circumstances would be ill considered”.

It is this recognition that reveals how US imports such as zero tolerance quickly lose their lustre.

We need teachers to make countless complex in-the-moment decisions, balancing the scales of consistency and flexibility, without the straitjacket of zero-tolerance policies that result in students too quickly spurned and excluded.

Alex Quigley is director of Huntington Research School, York and the author of the upcoming Routledge publication Closing the Vocabulary Gap. He tweets @HuntingEnglish