Should children who commit a crime be sent to prison? On an instant vote, my class was evenly divided. They started to debate.

“Children shouldn’t get away with it just because they are little,” said one.

“But they would miss their parents,” replied another.

A third wondered whether very young children even realised when they had committed a crime.

I said nothing. For more than half an hour, children listened to each other intently. Those who hardly said a word all week when we were studying Tudors or solving addition problems, spoke with clarity and assurance.

I was amazed and relieved. My first “Friday debate” was introduced as a desperate measure. Job-sharing a challenging Year 34 class at an inner London primary, we were starting to tear our hair out just a week into the new school year. By an accident of birth dates, we had inherited a class with more low-achieving, alienated, unconfident and unmotivated children than most classes in the school. The curriculum did not excite them - they know it does not belong to them. Few children seemed able to sustain concentration, but what really worried me was their inability to listen.

Schools have become obsessed with “rules” to “manage behaviour”. We didn’t want our classroom bound by lots of rules so we proposed one fundamental principle: that we will listen to each other with respect.

It was not working, though. We had to repeat instructions several times.

Children struggled to recall what they had been taught 30 seconds earlier.

Feeling depressed, I drew up a list of controversial subjects for discussion, cut them up and put them in a small tub.

The next day I introduced the word “debate”. In a debate the teacher says nothing - the children do all the talking, I explained. Ears pricked up.

There are no right or wrong answers, I added, just opinions. I could feel the relief among children cowed by targets and testing into self-censoring potentially “wrong” answers.

A child picked a folded paper from the tub and I wrote the subject for our first debate on the board. A buzz went round the room. I held an instant “secret ballot” - eyes closed, hands up (I kept the outcome to myself) and set up a “yes” chair and “no” chair, leaving a wide space between.

When chosen, contributors had to stand on the appropriate chair, explain why, and try to persuade others to agree with them. When several speakers consecutively went to the “yes” chair I invited those who wanted to speak from the “no” chair.

It ebbed and flowed. Then, one child walked past the “no” chair and stopped. “I’m standing in the middle,” she explained, “because I’m not sure. I don’t think six-year-olds should be sent to jail but some teenagers are really bad.”

That complicated matters. How old is a “child”? Other fence-sitters emerged, each proposing a different age of criminal responsibility.

Earlier contributors wanted a second bite but I gave first-timers priority.

As the numbers of virgin debaters dwindled I asked: “Has anyone changed their mind during the debate?” Several hands went up and they explained which arguments were most persuasive.

Aware that many children had exceeded their usual attention span several times over I closed the debate. I recognised the dilemma several children had expressed so I reworded the final question to ask whether children of primary-school age should be jailed for crimes. And before taking another secret ballot, I explained about abstention.

Opinion had shifted. I revealed the pre- and post-debate results. From being evenly split, now, nearly two-thirds voted against sending child criminals to prison. The first child to stand in the middle remained consistent and abstained.

Participation grows weekly. Every child in the class has contributed to at least one debate. Girls - a minority in class - are as vocal as boys. One child with a severe speech impediment has spoken every week and the others listen with respect.

They are gaining confidence in their own opinions and in their ability to evaluate arguments. They have also learned that you can disagree and remain friends. They are grasping the nuances of location. When we debated “Does every country need a royal family?”, one girl prefaced her intervention with: “I’m between the middle and the ‘no’ chair”. Children choose their position very carefully now. They are learning skills for life and not just for Sats. And, thankfully, their improved listening is gradually extending beyond the Friday debate.

To set up a successful debate you must judge what will divide class opinion. I made one wrong call - “Should you always keep a secret?” The children surprised me with near-unanimous moral certainty. One brave soul abstained; everyone else said “yes”.

After the vote I admitted that I disagreed. If someone was being bullied but told to keep quiet, they should break that secret, I said.

The children really look forward to the Friday debate, and so do I. But I am aware that, so far, I am setting the questions. Soon I will be asking them to propose issues for debate. That will truly test how far we have come.

Any thoughts? Write to primary@tes.co.uk

Set up a successful debate

* Use formal structures - “yes” and “no” chairs, votes.

* Look at controversial issues, especially those concerning rights.

* Vote in secret, so children are not influenced by friends.

* Ensure gender equality in participation.

* Encourage unconfident and marginalised groups to participate.

* Hold debate at a regular time.

* Don’t intervene: facilitate.