The thing is that not only can’t we re-write the past, we shouldn’t even try. This week, headlines have screeched that a Belgian court has ruled that the extremely racist Tintin in the Congo is not, in fact, racist at all. Even a glimpse at the images that the broadsheets are prepared to print seem to test that ruling, and certainly if you read the whole thing, you may wonder quite what a book has to do to be deemed racist in a Belgian court.

On closer inspection, however, the court has made a rather more sophisticated ruling than it first appears. They have ruled that the book, published in 1946, should not be banned in Belgium, because it wasn’t intended to incite racial hatred. And they are surely right. Tintin in the Congo was written in the 20s, and first serialised in the early 30s. It reflects the deeply patronising view of the Congolese which was, as the court stated, prevalent at that time.

And while we might wish that attitudes had been different, we do ourselves no favours pretending that they were. Under King Leopold II, between 10 and 13 million Congolese were obliterated. Twenty years later, as Hergé wrote his offending book, the idea that the Congolese – or any Africans – were little more than children remained intact. It is nothing for Belgium to be proud of. But banning books which show this is simply dishonest.

Time, as the old hymn goes, makes ancient good uncouth. Look at Conan Doyle’s The Sign of Four. Holmes’ description of the native inhabitants of the Andaman Islands would make us wince: 'They are naturally hideous, having large, misshapen heads, small, fierce eyes, and distorted features…. They have always been a terror to shipwrecked crews, braining the survivors with their stone-headed clubs, or shooting them with their poisoned arrows’. And that’s before he gets to the cannibalism.

But what good would it do to pretend that Conan Doyle would never have dreamed of saying anything so crass? He was a man of his time, just as Hergé was. By remembering what society used to deem acceptable, we remind ourselves how far we’ve come. Whitewash the past and we are condemned to vanilla revisionism (best summarised by a spoof poster for the film The Help, which neatly summarises the rather dubious politics of the film in two sentences. ‘White people solve racism. You’re welcome, black people’).

It’s worth bearing in mind that until a few years ago, mainstream book-sellers like Waterstones and Borders stocked Tintin in the Congo in their Children’s section. Now, the English language version of the book contains an introduction explaining its historical context. While the book is in print, it makes us re-evaluate how we deal with ugly history.