The one thing we did not set off to The Lord of the Rings with was high expectations. "A string of set-pieces jigging to the tune of a cash register" was one of the critic's barbs that stuck in the mind. Still, the combination of three children, half-term and lots of promises of treats for good behaviour made it seem like time to risk it.

Every Tolkien expert in middle Britain, to say nothing of Middle Earth, is up in arms about its cavalier treatment of the great master. Having managed to avoid reading the trilogy since I was eight, at least I went unencumbered by too much knowledge.

But there is no denying Tolkien's magical effect on small boys - and I had some curiosity at what a £12.5 million musical would look like. If you enjoy chilling spectacle for your steep West End prices you can't really complain.

Sinister black riders, orcs and a stringy Gollum in the early stages of decomposition do the trick.

The plot diddles along rather oddly, relying on flashbacks which would be mighty confusing to anyone who didn't know their Middle Earth inside out. The writing is pretty dreadful. That's the real disservice to the original: "May the hair on your toes never fall out," is about as good as it gets. I drifted off for a good half-hour worrying about property prices in London - and tuned back in, in the middle of a lecture about how the ring is the dissatisfaction and insatiable striving instinct in all of us.

Even I can see that something is going to go missing in boiling down a 1,000-page saga based on the great heroic myths into three hours. The children, reared on the books and Peter Jackson's spectacular movies, griped like true mithering experts about what was taken out. Less might well have been more here.

It's definitely better for children under 10 than older: the elves are twee, Gandalf is a po-faced old bearer of wisdom. But when the orcs are blasted through the audience, the tingling of real, pleasurable terror is there all right.

I stole a sideways look at three rapt faces, including one jaw hanging slack after the orc incident for a good five minutes.

If Tolkien, in all his majesty and absurdity, is going to be turned into a musical, this doesn't seem like such a travesty at all. Purists should stay home with the books. The rest of us can get a decent dose of it all in three hours flat and some very happy children. Which is fine by me. really.