few weeks ago I finished reading Tom’s Midnight Garden by Phillipa Pearce to my nine-year-old. The ending always makes me cry, a reaction that baffled my daughter because, as she pointed out, it’s happy.

You note I do not reveal the ending. Recently, I began to tell the story to the audience of BBC Radio 4‘s Woman’s Hour when the presenter Jenni Murray frantically stopped me. She rightly did not want me to spoil the book for future readers.

The power of the book, of almost any book, lies in the compulsion of the narrative and your involvement with the characters. That and the atmosphere created by the author, which, in Pearce’s classic, is a slightly quaint, innocent and magical feel that mesmerised even my Goosebumps-hardened child.

Now you might wonder why I have spent so long discussing my reading of such a familiar text. Well, two days after having been rebuked by Ms Murray, I received a copy of the new optional tests sat by Year 7. By coincidence, part of the paper was dedicated to the ending of Tom’s Midnight Garden.

Finding texts for exams is never easy especially if you want to use fiction because it means finding an extract. The problem with extracts, of course, is that they are isolated from the context that made them worth reading in the first place.

Recently examiners have tried to overcome this problem by theming papers, thus creating a new context. So the Midnight Garden extract appears in a paper entitled “Now and Then”. It could have been called “Past and Present”. The theme, you understand, is time.

But my objection is less that any child who has read the book will have an advantage over one who has not - though they will; nor is it that this exam will spoil the ending for a child who might read it in the future - though it may. No, my real objection is that the examiners utterly misunderstand how or why we might read a book like this in the first place.

The question that bothered me most asked these 11 and 12-year-olds to comment on the use of a colon and semi-colon in the passage. Not only is this an obscure and difficult question, it is also almost completely pointless, there only to check that the pupils have understood a rule of punctuation. Unless something changes, teachers will have to train children to get through this type of test and that will mean reducing lessons on works of fiction to grammar instruction.

In a recent interview, the author David Almond objected to the way in which his book Skellig had been used in the example materials that accompany the key stage 3 strategy. He disliked the fact that his text was being used simply as a vehicle for language instruction rather than encouraging pupils to engage with the story.

That same downgrading of the importance of critical engagement is evident throughout the optional tests, not just in the section on Tom’s Midnight Garden. In an article on a day trip to Hadrian’s Wall pupils are asked to find and explain abbreviations. At no point are they asked to read these texts critically or to offer their own interpretation. The questions, and by implication the answers, about the Hadrian’s Wall article demand pupils agree with the author that his day with three reluctant children was indeed fun.

For some reason politicians and policy-makers in this country have become obsessed with the idea that the only way to measure improvement is through standardised tests.

Although the tests in question here are notionally optional, schools and education authorities keen to show value added will feel compelled to introduce them and so teachers will be obliged to teach to them.

Once more we will have restricted our children’s experience and deprived them of the chance to revel in or reject the art that language produces.

Bethan Marshall is an English lecturer at King’s College London