When I originally suggested that my Teach First participant use his voice to quieten down an empty room of invisible children, he looked at me like I had finally succumbed to mid-term insanity.

He spent the first few attempts at trying to silence the “class” stifling laughter (and possibly wondering how he should go about requesting a different mentor). Fast-forward six months, and he now says those moments were the ones that truly transformed his classroom practice: they made him a better, more confident teacher.

As a mentor, you have too little time with your mentee and, more often than not, the time you do have can devolve into conversations about evidence standards or reflection logs. It’s also pretty easy for these meetings to fall to the bottom of your priorities and become about joint planning or just a quick “OK, you’re all right, yeah?” as you rush to tick off the next item on your unwieldy to-do list.

So, as a new teacher you can be a lone wolf as you learn your trade. Feedback comes through observations and drop-ins, or when you ask for it. It is a scab to be picked apart at in the mortuary of a mentor meeting. Sometimes, by that point, it’s too late - bad habits are harder to break than developing positive professional learning from the outset.

So the reasoning behind making my Teach Firsters teach to an empty room? It is a chance for them to practise, in front of an experienced teacher, and to reflect and adjust as we go through the process. It is an hour of one-to-one mentoring.

I model student and teacher behaviour during such sessions, and I can say with 100 per cent honesty that I am 10 times worse than any of the difficult students a teacher will face: I’ll swear, not listen and be the most obstructive I’ve ever been. Doing this enables the teacher to develop strategies and responses in a safe environment - it gives them time to think about what they are doing without worrying about disruption to other students’ learning. It’s essentially a form of simulation: they can make mistakes, pause and continue - each time learning more.

It’s also about pedagogy and delivery. New teachers can find it hard to develop their own persona and this active practice is ideal in helping them to form a teaching identity not based solely on their own education or what they’ve seen on TV - in my case, Dangerous Minds (unfortunately, I don’t look as good in a leather jacket as Michelle Pfeiffer).

Active practice is about helping the teacher to develop their persona effectively through feedback - it is an instant way of responding to a teacher’s approach without the embarrassment and disruption that would be in evidence if they were in front of a class, and you can work on multiple aspects of teaching in such sessions.

So how do you approach it? Telling a young teacher that you’re going to role play will likely make them clam-up quickly. Call it “active practice” instead and tell them they’ll get a lot out of it once they’re over the embarrassment of teaching to empty chairs.

The decision about what to focus on will depend on the teacher. I find it most effective when they tell you which area they want to work on. In the session, get them to show you what they’d normally do, then question them on it. It’s an opportunity for them to think about why they took a particular choice of action. If they’re stuck on a particular section, model it for them. Be cautious, though, as this isn’t about you showing them how good you are: always explain that they need to make it work to suit them rather than simply imitate you.

Despite going against everything I’ve heard said about giving feedback, I’ve found that, in this process, it’s easier to stop them if they’re making a mistake and guide them to the good practice. And when you’ve finished, get them to reflect on how their practice has changed.

The process can be stressful and frustrating for the new teacher. It can highlight flaws that they might not want highlighting and they may find it a challenge to show this vulnerability to you, so always highlight the positives as well.

It might sound weird. It might take a while for you both to loosen up. But believe me, teaching to an empty room is one of the best CPD tools you will ever use.

Benjamin Davey is an assistant principal at Bridge Learning Campus in Bristol