I no longer mark A-level homework.

It feels difficult confessing this. I still get the slight palpitations, the moistening of the palms, the nagging sense of guilt that I’m letting people down. I knew a while ago that I had to do something different, but it took time to really appreciate the extent of the problem and to have the courage to act.

It must have been about seven years ago when trouble first surfaced. Let’s call the pupil in question “Alice”. Each lesson, I’d ask for the maths homework to be handed in, which was usually a stack of questions from an exercise consolidating what we had studied in the previous lesson or, perhaps, a selection of past-paper questions.

Dutifully - and without the bat of an eyelid - Alice would hand her answers in and I’d mark them, impressed by her clear workings out and accurate answers. She was doing well. She was nicely on track to achieve her target grade.

And then we did an assessment. Alice bombed, but explained things away: she’d had a bad day, she was fine, she said. Give her a blank copy of the test and she would work through it again at home, she said. It all came back fine. She was back on course.

That is, until the next test, after which there were more interrogations and, finally, the truth came out: every night, Alice had been using a solution bank to peek at the answers. She was completely addicted, unable to work through a question without having a little look at how to get started or get past a tricky hurdle. She’d deceived herself and us, and was now in trouble.

As a group of A-level teachers, we met and decided on a course of action. Students would be told in no uncertain terms about the dangers of slipping into this behaviour. They needed to think of their long-term future, not of the immediate gain.

But sadly, with the ubiquity of smartphones, wi-fi and cheap data plans, the problem had become so bad that I decided there was only one thing to do: give up.

Now I no longer routinely mark A-level homework because it is a complete waste of my time. A worked solution to every single question in every single exercise in every single text book is out there somewhere online. The same goes for past exam papers, save the ones that are “locked down”, which we reserve for formal mocks. If students aren’t using online mark schemes to do the questions, they are using them to check their own work. Having a teacher going over it again is pointless.

Of course, I want to know how the students are getting on and how good their understanding is. But the only reliable way to do this is with in-lesson assessments where they cannot look at answers. I do these as starter activities and take them in to mark. Students are then expected to speak up about questions they need help troubleshooting and be honest about it.

It’s been a major change in mindset for me but at least I know that another “Alice” won’t fool me again.

Kester Brewin teaches maths in south-east London. While working as a teacher, he has been a consultant for BBC Education, and is the author of a number of books on culture and religion. He tweets @kesterbrewin

This article originally appeared in the 27 March 2020 issue under the headline “Why I refuse to go down the marking rabbit hole”