Well, someone had to do it  modernise Malory, that is. The original Morte d'Arthur isn't actually that hard once you get into the swing of it, and carries within its late medieval prose the unignorable frisson, which even the sternest historian cannot resist, that Arthur and his knights actually existed, and that the archaic manner of its telling takes us back in time to this magical past more effectively than any modern retelling: "And so he handled the swerd by the handels, and lightly and fiersly pulled it out of the stone, and took his hors and rode his way untyll his broder Sir Kay and delyverd him the swerd."

That hardly needs much effort to modernise, and in fact even needs some tidying up  "handled" and "handels", and the repetition of "swerd" suggest hurried writing. Ackroyd: "So he went over to the stone and, taking the hilt with both hands, lightly and easily took out the sword." We lose "fiersly", but you can see why. After 500 years, you can't expect us to have exactly the same worldview.

The original survives, at various removes, as persistent legend, whose best modern retelling is, in my opinion, John Boorman's 1981 film Excalibur, which had the misfortune to come out after Monty Python and the Holy Grail  which itself anticipated Boorman's visual magic, and ridiculous carnage.

That whole business with the Black Knight having all his limbs chopped off  "it's only a scratch!"  is not very far at all from what knights got up to in those days. You really couldn't ride for half an hour, it seems from Malory, without being challenged by someone with a grievance, and as trial only existed by combat, the victor having proved his case according to the will of God, it wasn't easy to get out of a joust if your opponent was insistent.

There is also the plot-furthering wrinkle, which for all I know is an invention of Malory's, that you could fight someone without knowing his identity, as long as he swapped shields with someone and kept his visor down. (Best prose retelling of the Arthurian legends: TH White's The Once and Future King. I still recall the effect on me as a child of the scene of Morgan la Fay boiling a cat in order to pick out the bone that would make her invisible.)

But Malory is, in my treasured sturdy OUP hardback of 1954, 900 pages long, and all this biffing, and the (at first) rudimentary explanations of motive, and the weird geography  the action zips all over the country so quickly it is as if there is a super-efficient pre-Beeching railway network in operation  can get wearying after a bit, and his retelling of the Tristan and Isolde story is generally agreed to be far too long and confused. So Ackroyd has ditched about two-thirds of the original, but with the obvious intention of keeping its flavour.

Well, you can see from the quotations above what we have lost, and what we have gained, in the matter of style. Adam Thorpe wrote a very perceptive and informed, but also in my view somewhat harsh review of Ackroyd's Arthur in this paper, and in fact he might have been the better person to do it, and all sorts of episodes have had to go (we miss a large part of the explanation why Gareth's death at Lancelot's hands is so grievous), and at one point Lancelot wakes someone up in Ackroyd by tapping him on the head with the pommel of his sword, not in Malory, and so on; but this a perfectly forgivable intrusion of invented detail.

It is, after all, all invented detail, and Malory made very free with his French sources. (It is odd that as Malory's writing gets better, and the further he deviates from his sources  the characters have proper depth by the end, and can truly be called "characters" rather than just suits of armour with names attached to them  he makes more allusions to the French texts he's using, as if he's visibly gaining in confidence.)

It is, though, one of the great stories, a beautiful, tragic myth of love and power, and if you are not fighting back a tear by the end of it, thou hast a heart of stone, sir.