Until Saturday (March 14).

It’s not so puzzling when you think about it. Having grown up in the stuffiest of English families, of course David Windsor, later to become Edward VIII, (briefly) would be fascinated by the lively Mrs Simpson.

The Americans don’t have our awe of royalty. That’s why Michelle Obama stepped right in on her visit to London and gave the Queen a hug. All she saw was a little old lady in her 80s. What British woman would have dared to embrace the monarch, even if she was married to the most powerful figurehead in the world?

And neither do the Australians share our quivering reverence for blue blood. That’s how Lionel Logue (played superbly by Jason Donovan in a relaxed, natural performance) was able to help the stammering, stuttering Bertie who later became King George VI (played elegantly with all the required stiffness by Raymond Coulthard).

This production, directed by Roxana Silbert, evokes the stultifying formality of the period, pierced only by spikes of outrageousness that had to go three steps further to have any effect. So of course, Wallis Simpson must have a dancing party in the royal household only six months after the death of King George V. She must sleep in Queen Mary’s bed.

The problem with a play following a film is that the stage version is in danger of appearing static. The scenery certainly is. The costumes won’t be so gorgeous, there is no music to tear at your heart. There are no tricks, you have to rely on great performances.

Donovan and Coulthard deliver this with good support from an ensemble cast, particularly Katy Stephens as Myrtle Logue.

It’s a history play, you can’t expect surprises but you do see an elucidating glimpse of the past.