You don't have to love the English language to disapprove of The Da Vinci Code. A passing respect for your mother tongue is enough to make you wince when Dan Brown takes a chainsaw to the old girl and slices her into clichés and easy-to-assemble sentences. Why millions of people have bought the literary equivalent of an Ikea flatpack is a riddle beyond Brown's power to solve. It is a page-turner, to be fair, with a mystery that pushes you past the arthritic dialogue of the stock characters.

But when readers turn to the final page with the reasonable expectation that the mystery of the Holy Grail will be explained, Brown refuses to oblige. Like the mediocre reporter who can't get to the bottom of a story, he says words to the effect of 'perhaps we'll never know the truth' and leaves it there.

I'm not spoiling the ending by telling you this. The problem with The Da Vinci Code is that there is no ending to spoil.

If there has been a worse book published in the past 25 years, then Holy Blood, Holy Grail could well be it. Its three authors present as plausible historical speculation their theory that Jesus did not die on the cross, but had a child with Mary Magdalene. Like so many expats, they moved to France, and their descendants became Merovingian kings in the Dark Ages. The heirs of Jesus survive to this day, feared by the Vatican and protected by an enigmatic institution, the Priory of Sion.

The authors did not withdraw the book when journalists found that their claims about the Priory of Sion came from documents forged on a cheap stencil by a French neofascist conman called Pierre Planchard, who said he was the rightful Merovingian king of France. There was no need to. Exposure of the hoax did not dent their sales, which now stand at around two million. Nor has it harmed The Da Vinci Code, which repeats parts of the story. Around five million British readers have bought one or both of these books. That the authorities allow them to vote and serve on juries should terrify everyone who cares about the good government of our country.

How much of The Da Vinci Code is - ahem - 'borrowed' from Holy Blood, Holy Grail is the subject of the plagiarism case at the High Court in London that enters what should be its final week tomorrow. 'Too bad they can't both lose,' said Henry Kissinger about the Iran-Iraq War and I felt the same when I went to the court.

Apart from the feuding authors, no one else seemed to care about the result. The court journalists were pleased that their reports were going round the world. The lawyers were upholding the highest standards of the Bar as they declaimed 'the Grail has spawned legends, wars and quests' and 'the bloodline of the Merovingians continues to this day' without giggling once.

The only person who looked disconcerted was Mr Justice Smith, a plain-speaking judge from the Northern Circuit. As he scratched his wig and snorted into his bushy black moustache, I wondered if he was trying to work out how his blameless legal career had led to him having to listen to such tosh.

One copyright expert I spoke to shared the general feeling that it didn't matter who won. Mr Justice Smith's verdict would present no wider threat to the business of producing fiction and non-fiction, he said, pointing to a near identical case in 1980.

An author called Trevor Ravenscroft had ignored the Holy Grail for once and concentrated, instead, in The Spear of Destiny on the weapon used to pierce the crucified Christ's side. Ravenscroft said it had brought evil through the ages and inspired the Nazis. He successfully sued James Herbert, a writer in the Dan Brown mould, for stealing his pseudo-history. The sky didn't fall in and everyone from potboiling novelists to learned academics carried on as before.

Other lawyers are not so sure. David Hooper, a specialist in intellectual property, said the case was something new. The Holy Blood authors are not saying that Dan Brown had copied chunks of their work verbatim. Instead, they are suing him for taking some of their ideas, researching them, playing with them and turning them into a novel. If they win, Hooper believes a chill will go through cultural life as publishers face the next to impossible task of separating original thoughts from other people's thoughts.

Restricting free use of ideas is the spirit of the age. Firms have claimed copyright on plants and parts of the human genome because ideas are worth more than all other assets. The World Trade Organisation recognised this when it made international acceptance of intellectual property rights one of the central aims of the drive to globalisation in the Nineties.

I hate to be the one who has to say it, but Dan Brown needs to win. If he doesn't, free thought may be stifled in the name of protecting ideas.

Furthermore

An African crisis Europe can't ignore

Because the Archbishop of Canterbury preferred twittering about gay vicars to speaking out on crimes against humanity in Sudan, we have had to look elsewhere for men and women with the moral strength to bear witness. On Friday, the staff of the United Nations High Commissioner for Refugees stepped forward to fill the gap. Unfortunately, they said they were planning to cut the number of refugee workers in Darfur by 44 per cent. State-sponsored violence and counterattacks by Darfurian forces on aid convoys and civilians were making relief work impossible.

You cannot exaggerate the seriousness of the withdrawal. The African Union's peacekeeping force in Darfur is understrength, ill-equipped, badly led and wholly unable to do the job. The Islamists in Khartoum are threatening to set al-Qaeda on the UN if it sends in its own troops. Meanwhile, Sudan is aiding rebel forces in Chad and Chad is aiding rebel forces in the Sudan. War between the two countries is a possibility.

We cannot bolt the gates of Fortress Europe and pretend the crisis has nothing to do with us. We ought to have learned by now that the people smugglers will bring in asylum seekers and, with them, new racial tensions.

We should also know that the ability of Sudan's rulers to get away with promoting terrorism could lead to Islamist attacks on the 'far enemy' in Europe as well as targets in their backyard.

While we wait for the predictable consequences, this column will have a new feature: What the Archbishop of Canterbury Won't Discuss. Coming soon: 'The contribution of the Pope's condom ban to the Aids pandemic'. I will run it to coincide with the archbishop's visit to the Vatican.

Invasion of the story snatchers

The only sensible remark made about John Profumo's sharing of Christine Keeler with a Soviet agent came from Lord Lambton, right, himself a victim of a later sex scandal. It could only have mattered if the affair had been platonic.

Just so. Nothing in the Soviet archives shows that Profumo had the urge to betray his country. Other urges were on his mind. At least in 1963, the press felt the need to justify running a juicy story. The Secretary of State for War meeting a Soviet naval attaché and a call girl at the pool of the proprietor of The Observer was more than enough.

It doesn't work like that now. The current owners of The Observer enforce the highest standards of poolside behaviour, while today's newspapers don't require an excuse for invading privacy. They just invade.