Finally, the trousers are coming off the Government’s education policies. The news that teenager Paul Erhahon, who was murdered by a gang of youths last Friday in a quiet London suburb, had suffered an earlier knife attack at school has, together with other teenage stabbings and murders, offered a glimpse of the sordid underbelly of violence in our classrooms. Many of these violent teenage disputes – there have been seven murders over the past 11 weeks in London alone – have their origins at school.

It should come as no surprise that in these menacing settings, not much learning is going on: Government figures show that one in four pupils is failing to make progress or is getting worse in key subjects during their first three years at secondary school. Almost 150,000 pupils make no progress in science, while 85,000 fail to improve their grades in English and 30,000 in maths.

As a teacher in various comprehensive schools for the past 15 years, I know that the problem isn’t with parents, pupils or teachers – it’s the result of shockingly poor, incompetent and meddling governance.

Ten years on, and untold billions spent, but Blair and his cronies have failed to sort out the mess left behind by the outgoing Conservative administration in 1997. The Tory government, back in 1989, instituted a complicated national curriculum that most schools struggled to implement properly. The teaching profession was crying out for simplification, but instead, Labour added more complexity. Vital subjects such as English, maths, science and modern languages were downgraded, Mickey Mouse subjects such as media studies and hairdressing were introduced.

Schools were – and still are – rewarded for teaching these subjects at the expense of the more difficult and worthwhile ones. The result? Three quarters of 16-year-olds fail to attain five good GCSEs, including English, maths, science and a modern language, while half of all pupils leave school with poor literacy and numeracy skills. Britain now lags well behind all the major Western countries in its teaching of the sciences and maths.

The Government has also fought hard to make our schools breeding grounds of misbehaviour and chaos. Its much vaunted policy of "inclusion", whereby pupils with special educational needs are to be "integrated" into ordinary schools, has caused all manner of classroom disruption.

Pupils with severe emotional and psychological difficulties used to be taught in "special schools" by specialist teachers. Many of these establishments have been closed, nearly 100 since Labour came to power. Teachers who specifically dealt with misbehaviour – pastoral carers – have been replaced by "teaching and learning" mentors who spend their time massaging statistics, not dealing with indiscipline. But it is exactly these teachers who are needed to stamp out the bullying that possibly led to Paul Erhahon’s murder.

Parents understand this and are increasingly educating their children at home: at the last count, there were 50,000 of them. Truancy has rocketed to 217,300 persistent absentees last year: many children simply don’t feel safe in school. No wonder. In this environment, the idea of teaching and learning is laughable.

The only way to raise standards is to give educational establishments more freedom to create a school and curriculum responsive to our ever-changing world. But the Government has stripped most schools of the power to select children by academic ability or special abilities.

The distinctive ethos of the school where I teach will be gone in a few years’ time. It attains great results because it has had the power to decide its own affairs and could select pupils enthusiastic about music,drama and sport. In future, it will no longer be able to take a wide cross-section of pupils and will probably have to take pupils locally in the name of "equality". Clever but poor students will no longer be able to attend, but children of wealthy homeowners in the area will.

At the last election, the Tories had the best solution: to set a scheme whereby parents would be given a voucher, worth £5,000 approximately (what the state spends on every pupil), and could "spend" it at the school of their choice. This would have introduced a true market system into education, made schools responsive to the needs and wishes of their clientele, given them the freedom to sort out their own affairs, and pushed up standards.

Now, under Cameron, they’ve backed off the idea and are offering more centralised diktats instead: they want all schools to put pupils in sets of similar ability. Sometimes this works, but in other schools it is not appropriate. The Tories think directives from Whitehall can solve everything, when usually precisely the opposite is the case.

This Government’s failure to improve the education of our children is nothing short of a national tragedy. Above all, it is for this that Tony Blair should resign, having promised so much, while delivering absolutely nothing but hot air and also driving many of our schools back into the dark ages.

Urgent action is needed if we are going to reverse this inexorable decline in standards. Alas, no one seems to have the courage to do anything except spout platitudes and spin. If we’re not careful, in a few years’ time our country will be in a similar downward spiral to our schools, run by a bunch of illiterate louts, victims of this Government’s wretched education policies.

Francis Gilbert’s ‘The New School Rules’ is published by Piatkus on May 24