In January, culture minister Tessa Jowell closed her speech to the Oxford media conference with a ringing endorsement of media literacy, her “favourite subject.” This new form of literacy, she observed, “is as important to our development as was universal literacy in the 19th-century (when) the written word was the only passport to knowledge.”

The conference delegates applauded enthusiastically. As a teacher of film studies and media studies, I might have been expected to clap even longer and louder than the rest. After all, an increased emphasis on media literacy means more students on my courses, thanks very much. But I clapped as much out of good manners as real enthusiasm.

Sure enough, I’m all for media literacy; more than ever, we live in a world saturated with media messages that should be examined and evaluated. But I’m sometimes concerned that this relative newcomer to the academic scene is set to overshadow more traditional notions of literacy.

What worries me is my students’ work. While a small minority show real talent in their writing, a lot struggle with spelling, punctuation and sentence construction. But even these are streets ahead of the many others whose writing is no more than a jumble of possible meanings. Other teachers I know say likewise. We all ask the same: how can these students have gained a GCSE in English Language, some with a middling if not a higher grade? And when they go on to pass their A-levels, we are yet more perplexed. How on earth will they cope at university, we wonder.

Not very well, according to a recent Nuffield Review report. Asked to comment on the standards of literacy of school-leavers, focus groups of 250 lecturers and tutors at 16 universities were less than complimentary. “They can’t even write in sentences. Their spelling is appalling. They can’t be understood,” railed one tutor. “Basic writing skills are lacking,” an admissions officer grumbled. “They cut and paste essays from the web,”

complained another tutor. “Reading books is a skill which has been lost.”

Clearly, we live in a society that has big problems with standards of literacy. Tessa Jowell’s speech made no mention of this. But if she is serious about the importance of media literacy, she should recognise that a prerequisite of this new literacy must be proficiency in the old.

It’s no exaggeration to say that, by the time they reach 18, today’s students will have seen around three times as many films as I saw in that time. Not only do they regularly go to the cinema, but they also download films as well as rent, buy, borrow and copy DVDs. They spend hours on the internet, mostly on image-rich sites. In much of the time that remains, they text friends, watch telly or settle into an iPod-induced trance.

So when do they read? Well, mostly they don’t. Students say that, aside from the Harry Potter series (praise be to JK Rowling) and, occasionally, Terry Pratchett and Helen Fielding, they seldom if ever open a book other than a college set text. Of course, there are exceptions - one of my students raves about Jack Kerouac - but they are as rare as they are gratifying. On the other hand, students are good at reading images. Asked to analyse the opening of Chicago, say, or to comment on the connotations of the studio design for television news, many will offer intelligent, incisive spoken judgements.

On the page, it’s different. Spelling is arbitrary, punctuation primitive, meaning muddled and ideas undeveloped. Saying so might sound fogeyish, but it seems that, for many young people, the image has gained clear ascendancy over the written word. You don’t have to be Lynne Truss or John Humphrys to lament this; you just have to mark essays by students who, despite their clear understanding of ideas and issues, just can’t get it down in anything like acceptable language.

In other words, proper media literacy cannot and should not be achievable without a high standard of conventional literacy. As the best media critics show - Clive James and Thomas Sutcliffe, for example - only through authoritative, inventive expression can media output be properly assessed.

As things stand, the examination boards encourage disregard for accurate writing by passing candidates whose written work might gently be described as unformed. Yes, nurture media literacy by all means; first, though, might we not urge students to show at least as much respect for the word as for the picture?

Laurence Alster teaches media and film studies at South Downs college, Waterlooville, Hampshire