Wicked must be the most raved-about musical of the past two decades.

Like half the population I’ve wanted to see it for years and I know all the brilliant songs by heart.

What a set-up for disappointment: but Wicked is one of those rare shows that surpasses the hype.

It’s absolutely, utterly wonderful, everything you want a big musical to be, something you can sum up in one word: “wow”.

This is the story of the Wizard Of Oz from another angle, with Kansas girl Dorothy only seen fleetingly in silhouette.

We follow green-skinned Elpheba on her journey from magic-school student to Wicked Witch.

There are witty links to the famous story – like how the scarecrow, tin man and lion came to be – but that’s not really what Wicked is about.

What makes the show gripping, stirring and ultimately heart-breaking is the relationship between Elpheba and good witch Glinda.

They start out as enemies but gradually forge a friendship that turns the entire Oz story on its head.

The songs alone would have made Wicked memorable – they’re among the best in Broadway history – but it’s the witches who really make Wicked a classic.