The unions claim to represent teachers' interests, but at what cost to pupils? (Reuters/Andrew Winning) 

One day, during my PGCE teacher training, we were all herded into a large hall where the teaching union representatives sat smiling behind their stalls. We dutifully queued up and signed on the dotted line. The option of not belonging was, in essence, hidden. We agreed to allow about £150 to leave our bank accounts every year because that's what teachers do: we belong to unions. Except for me, that is. I had to use the loo, was bored of queuing and left with the intention of signing up later. But when September came, I got busy working, and couldn't see the point of paying money to a union for nothing. In those first couple of years, every teacher who heard of my lack of protection from the big bad bosses (whom I have never met) rushed to warn me that I was putting my life in danger. Even if I didn't worry about being fired for incompetence, what if a child were to accuse me of something? Who would defend me? Eventually, I capitulated and signed up. 

In state education there is a kind of social obligation for a teacher to belong to a union. The most ardent union supporters among teachers belong to the National Union of Teachers (NUT). They tend to be very loud in the staff room, forcing others to toe the line. They push the mantra of evil senior management exploiting staff, and bully younger teachers to buy into it. The idea of holding colleagues to account or requiring high standards of teaching is not on their agenda. Good teachers keep their heads down, ignore the fact that they are paid the same or considerably less than the worst teachers, and get on with the job.

Interestingly, it is not just bad teachers who are vocal in support of union power. The union grip on schools, both psychologically and socially, is more pernicious than that. Some young teachers, good and bad, are radicalised by senior ones. The veterans seek out the more vulnerable and awkward young teachers, who may simply be looking for a club to belong to, or want approval, a voice, a reason to feel valued.

Most teachers believe fervently in their teaching union. If you ask them why, they will say something about being protected from evil management. If you're a bad teacher, there is some sense in this, for unions are powerful and will stand in the way of a head trying to get rid of a bad teacher. Heads know that firing a teacher is practically impossible in an ordinary school beholden to the local authority. It is estimated that in the last 40 years only 18 teachers — out of the 500,000 in the UK at any one time — have lost their jobs because of incompetence. Such is the strength of union power. Unions have persuaded most teachers — whether good or bad — that the protection of bad teachers is in the interest of all.  

In an academy which is independent of the local authority, unions do not have the same kind of power. Free schools are essentially the same as academies in terms of the freedoms they retain. Academies and free schools break up the monolithic structure of state education. Instead of taxpayer money going to the local authority, where bureaucrats decide how to use it in providing services to schools, the money is given directly to the schools, and heads decide how that money should be spent. Academies and free schools can set their own pay and conditions (thereby giving heads the option of rewarding good staff financially) and employ non-qualified teachers who have missed the PGCE herding-into-the-hall moment. With the centralised state education system broken up, unions will no longer be able to call for national strikes with ease. More importantly, they will no longer be able to protect bad teachers. A more open system will reduce union power. 

So it should come as no surprise that unions are pumping huge amounts of their members' money into an anti-academy, anti-free school campaign. They pay members' travel expenses to attend anti-academy rallies, spread propaganda about free schools selecting pupils (simply not true and not allowed) and spend thousands on flyers in every staff room, giving teachers ideas on fighting a head or chair of governors who may want to turn their school into an academy. The number one item on their agenda is to stop the current revolution of academies and free schools in education. After all, if unions become redundant and lose members, who will pay the union bosses  earning more than £100,000 a year?  

Unions naturally can't say this out loud. Instead, they pretend they are defending teachers and children. They argue that Michael Gove, the Education Secretary, is destroying our education system, our values, and an ethos that serves children well. They deny simple facts that prove our education system is failing: for instance, that more than half of our children are unable even to get at least five C grades at GCSE, including English and maths. Even worse, a staggering 84 per cent fail to achieve five C grades at GCSE in the academic subjects specified by Gove's new English Baccalaureate: English, maths, science, a foreign language and either history or geography. These are the core subjects we take for granted that our children are learning at school — yet the vast majority are leaving school without a pass in these exams.

I believe the basic concept of a union is admirable. Unions are meant to protect workers against exploitation. If only this were what modern teaching unions were doing. We teachers sign up for them because we believe they will help us when in need, and ensure our profession is highly regarded. But they keep poor teachers in post, and give us all a bad name by lowering standards. Retaining bad heads also serves the unions because incompetent heads can then exploit struggling teachers (rather than help them to improve) and the unions appear indispensable. The result is that children are left to rot in chaos, the public believes we teachers are inadequate and lazy, and the teaching profession is considered unsavoury by many talented graduates. 

Degrading our profession, as teaching unions are doing, helps neither teachers nor children. If the unions are really keen on protecting the worker, where were they when I lost my job? I suspect that had I given a speech at an NUT meeting rather than the Conservative Party conference, and then been sent home or suspended, they would have been up in arms and marching in the streets. As it is, my union not only did not come to my aid, but waited until a couple of months after I had left my job to get in touch. Then they rang and said: "Now that you're no longer in teaching, shall we just get you off the books?"

The other day I was on the radio discussing my new free school —Michaela Community School (www.michaelacommunityschool.co.uk) — with a union leader who claimed: "The quicker teachers like Katharine Birbalsingh lose their jobs, the better!" Does he mean that teachers who vote Conservative should be fired? Or is he saying that teachers who criticise the system or hold opinions not endorsed by their union should be forced out of the profession? Somehow, we have moved away from the idea of unions protecting workers to one which allows unions to shove their political ideology down the throats of their members and insist that they fall into line. Far from unions protecting teachers from big bad bosses, it is big bad bosses who seem to run the unions. 

Unions campaign for skill — based learning and against knowledge—based learning, in spite of the fact that children in private schools achieve better results with knowledge — based learning at the heart of their curriculum. Children in our state sector are failing partly because of a lack of academic rigour. The unions are the ones who ensure that unruly behaviour is accepted in schools, by denying that it is happening. Meanwhile their members are leaving the profession in droves — a third of them leave in their first term — not because of poor pay, but because of chaos in the classroom. Times Educational Supplement discussion forums show how bad the situation has become. Yet the unions, who should be protecting their members, deny what infuriates them most.

Some unions oppose reforms allowing teachers to search pupils' bags for weapons. It beggars belief that they should want to take such powers away from teachers. To top it off, the acting Deputy General Secretary of the Association of Teachers and Lecturers (ATL), Martin Johnson, says that we should abandon the national curriculum altogether and have lessons in walking instead. Yes, lessons in walking: "There's a lot to learn about how to walk. If you were going out for a Sunday afternoon stroll you might walk one way. If you're trying to catch a train you might walk in another way and if you are doing a cliff walk you might walk in another way. If you are carrying a pack, there's a technique in that. We need a nation of people who understand their bodies and can use their bodies effectively." If this isn't enough to convince people that unions do not speak in the interest of either teachers or children, I don't know what is.

But persuading teachers that their union may not be acting in their interest could be difficult. The culture in schools is such that rejecting the role of NUT representative or questioning the union mantra is considered to be letting the side down. At the free school I am setting up, I would be happy for teachers to belong to any union they may choose because I believe in freedom and actively encourage people to debate alternative ideas. 

I only wish the unions could do the same. They are meant to do right by teachers. The irony is that if they did, they would also be doing a marvellous job for our children: staff would be held to account, bad teachers would be weeded out, the public would respect us, and both teachers and children would fare better in the classroom. The concept of a union defending the worker is one which we should seek to rebuild, instead of allowing current union political ideology to consume everything in its wake.

I am not alone in thinking this: according to a survey by the National Foundation for Educational Research, only 21 per cent of all teachers think schools have enough freedom to sack incompetent colleagues. That would tally with what I used to hear teachers say behind closed doors. They hate the fact that children are let down by less competent staff. But as with everything in our broken education system, teachers have to shut up. 

Wake up, teachers of Britain — you are being duped. Deep down, I know you know it, just as we all know standards have dropped, behaviour is out of control, and our children are being failed year after year. Unions don't care about teachers. Neither do they care about our children. When you look carefully at what they're doing, it's clear they only care about themselves.