In recent years we have witnessed disturbing attempts by some politicians to take control of the national curriculum. On many occasions their efforts have demonstrated their ignorance or prejudice or, worst of all, their desire at all costs to attract supportive headlines in national newspapers.

This is especially true with respect to the teaching of English. When they were at school many highly educated men and women over the age of about 55 were taught untruths about the English language. If since school days they have never read any books about language (and this seems true of many of those politicians who pontificate about standards in English) their ignorance has remained untouched. Indeed, many are dogmatic and even belligerent in support of the language theories they imbibed at school.

It is very hard for old people to accept that cherished ideas about language, which over the years they have forced upon their own children, are, in fact, nonsense. The best-known example is the supposed rule that we should not split the infinitive, although in speech our leaders, including the Prime Minister, do so all the time. We are accustomed to the fact that in medicine or science the popular theories of the 1940s and 1950s were often inadequate. It is more difficult for many old people outside the universities or teaching profession to accept that the same is true about the English language.

This is why this year’s Reith Lectures, given by Jean Aitchison, Rupert Murdoch Professor of Language and Communication at the University of Oxford, are very welcome, and why she has received some foolish and even rude replies in the press. Her first lecture confronted the old-fashioned pedants head-on.

Language always exists in a process of dynamic change. When I was at school in the 1930s and 1940s I was taught that the English language should conform to the rules of Latin, that its forms are logical and that its vocabulary and grammar obey immutable rules. This is all nonsense, as linguists have shown for over 100 years.

In her first lecture Jean Aitchison tackled the widespread view that the English language is in decay. This view has cropped up regularly over the centuries. She compared its proponents to cranks who argue that the world is flat. The real problem, she argued, is that foolish pedantic rules make people insecure, afraid to express themselves with confidence. She advocated a policy of “liberty within limits”, a major theme which her five lectures illustrated through a series of lively and entertaining examples.

She told us how the phrase “for you and I”, in place of the presumed “correct” form “for you and me”, came out top of the complaints in letters written to the BBC about language.

Yet several well-known figures have used it in public quite recently including Oxford-educated Lady Thatcher, who commented that “it’s not for you and I to condemn the Malawi economy”. In the recent repeats of Whatever Happened to the Likely Lads?, Bob, trying to be posh, made the same error. There is a surprising mismatch between what people condemn and the condemned forms they use without noticing. Jean Aitchison wants the next generation to shake themselves free from this cobweb of worries.

When linguists explain that language is in a process of change, that the vocabulary and grammar of old people varies in subtle ways from that of highly educated young people, many traditionalists presume that linguists believe that in English usage anything goes. They are desperate to maintain a standard of absolute conformity. It is indeed true that Jean Aitchison argues that “correct” English is difficult to define, and that we all adapt our English to what is appropriate in different circumstances. We change our speech according to whether we are speaking to a child, to a friend in a pub or to a prospective employer at an interview.

But in her fifth lecture Jean Aitchison insisted that there are genuine rules, and she particularly attacked gobbledygook, the use of pretentious and unintelligible jargon. She said that if people clear their minds of pseudo-worries, such as anxiety about split infinitives, then they might have more energy left to notice genuine confusions.

I wish that in her first lecture in January Professor Aitchison had emphasised this more strongly. Since the publication of the Cox English National Curriculum of 1989 I have repeatedly been attacked as a relativist. We need to say as loudly and as often as possible that knowledge of the true nature of language change must accompany a concern for high standards of lucidity in speaking and writing. This was a central theme in the 1989 curriculum.

I would welcome a return to the exercises in precis writing which I practised when I was at school. I found the task of reducing a document to 300 or so words an invaluable training. It demands strict adherence to the rules of punctuation, spelling and grammar, the ability to condense a prose document to its essentials, and to write lucidly without wasting words. In real life this ability is of great importance in business, politics or the professions.

In her lectures Jean Aitchison provided up-to-date accounts of the origins of language, the way children acquire language and how we remember the huge web of words in current practice today. She recounted the Chinese folk tale about a frog which had lived all its life in a well. One day it hopped out, and was astonished to find what a limited view of the world it had always had. Her aim is to offer similar enlightenment to the traditionalists whose nostalgia for past usage obscures for them the rich varieties of modern English.

I get very angry when people say there is no good literature published in recent years. Toni Morrison’s Beloved (1987) is a great novel. Tony Harrison continues to publish poetry and dramatic adaptations of the highest quality. Translations of works such as Gabriel Garcia Marquez’s One Hundred Years of Solitude are read by thousands. Language is alive and kicking; stupid nostalgia for the linguistic usages of the past is a depressing phenomenon.

This is the justification for courses in knowledge about language, a central concern of the 1989 English national curriculum. The Government’s decision in 1991 to suppress the Language in the National Curriculum (LINC) programmes has done immense harm to the vitality of English studies. The Warwick research into the classroom implementation of the English national curriculum (published by SCAA in 1994) showed that when in 1992 the Government decided to rewrite the English curriculum many teachers no longer bothered with knowledge about language, and abandoned the project.

I hope Jean Aitchison’s Reith Lectures will help to arouse popular interest in language. Only in this way will standards in English improve. Only in this way will teachers and pupils understand the kinds of “liberty within limits” which produces great writing.

Professor Brian Cox’s latest book The Battle for the English Curriculum, is published by Hodder and Stoughton. He is chair of the Arvon Foundation and of the North West Arts Board