While Broadway nervously approaches mass reopening in September, with casts and creatives terrified by the Delta variant, much of London’s West End has been happily chugging along since spring.

Producers there have had to adapt to — or, in the case of Andrew Lloyd Webber, angrily shout about — constantly shifting rules, and bowed to the reality that it’s now or never. 

Sorry, Mary Poppins. Nothing these days can be practically perfect in every way.

Still, on a recent trip to London, I found a jaunty mood among locals and relatively full houses at long-running musicals. It’s the exact landscape Broadway is dreaming of.

Straight off the tarmac, I stopped by the Kings Arms pub in Chelsea, masked up, and asked the bartender if I was allowed to sit on a stool. In a thick Slavic accent, he replied, “Back to normal!”

That same just-like-before vibe is evident at the shows: they’re mostly mask-less, everybody has a drink in hand and there are happy families aplenty. Heaven.

UK theatergoers are different from Broadway, though — and so are the much cheaper ticket prices. There is a robust domestic audience for theater in Britain, whereas Broadway depends heavily on international tourists, most of whom are locked out of the country right now, and on corporate expense accounts.

And, yes, the West End hasn’t been without its struggles. Over there until Aug. 16, if a single cast member caught COVID-19, the entire show was forced by a wishy-washy government to shut down for 10 days. Regardless of others’ test results. Many did, and some productions took a nearly $1 million hit during their hiatus.

Still, they carried on. After the Disney musical “Mary Poppins” opened Aug. 7, a production source looked at me with desperation and said, “Nine. Days.” That’s how long they needed to make it without a COVID case and avoid a costly closure.

“Poppins,” which stars a mischievous Zizi Strallen as Mary and Broadway’s Charlie Stemp as Bert, passed the finish line without a hitch, and now the risk of cancellations is thankfully much smaller for everyone in town. 

Onto the shows.

I first revisited a production I adored in 2019, “Joseph and the Amazing Technicolor Dreamcoat,” which is back for a sparkling summer engagement at the London Palladium.  

Director Laurence Connor’s staging blows the dust off the old papyrus by injecting cheeky humor (the Old Testament isn’t exactly known for the jokes), doubling down on the party energy and including the child chorus in more clever ways than simply having the kids “ahhh ahhh ahhh” like human kazoos.

Jac Yarrow is luminous as ever in the title role, but the young actor has found deeper meaning in his songs, and Jason Donovan is somehow having even more zany fun as the rock-and-roll Pharaoh than he did two years ago. But the best switch-up is casting Linzi Hateley (true Broadway buffs will know her from “Carrie the Musical”) as the Narrator. Get this — it’s a role she last played 30 flippin’ years ago.

That tidbit alone is touching. Much as snobs like to mock “Joseph,” the unpretentious show has an admirable, timeless message about passing stories down to new generations. Who better suited to such a task than a woman who tackled this same part on the same stage three decades earlier? It helps that Hateley, who shares the role with Alexandra Burke, brings a moral authority to the Narrator that comic actress Sheridan Smith couldn’t, and that she sings the hell out of it. 

The West End’s “The Phantom of the Opera” has also sharpened and heightened each sensation, for better and worse. 

The show’s “phans” — some of whom are serial-killer-like in their intensity — have been miffed that the set at Her Majesty’s Theatre has been redesigned somewhat from Hal Prince’s original. Almost everything is new, even if it doesn’t look that way, and that means that Maria Bjornson’s iconic candelabras are shiny instead of dull and the costumes’ colors really pop. The spruce-up looks good and it had to be done.

Not so welcome is a flat, golden proscenium arch that underwhelms from the stalls, and a massive new Pegasus statue, which while grand and impressive, robs the best moment of the show of power. I’m told there are no plans to bring these new elements to Broadway.

But Killian Donnelly would not be turned away. The actor wisely channels Michael Crawford more than most Phantoms do nowadays. Yes, he has a sublime, booming voice, but through his creaturely speaking voice and movement, he embodies what it is to be an outcast — not a GQ model who slapped on a mask for kicks.

The Christine alternate, Holly-Anne Hull, also returns to her role’s roots. Whereas many actresses in that part are instant divas who are as relatable as Maria Callas, when Hull emerges from the ballet girls to sing “Think of Me,” you really can’t believe it. She gradually, methodically makes you believe she’s an opera star.

I ended on “Hairspray,” that boppin’ ’60s-set musical about a diversifying Baltimore, which is back at the London Coliseum. It’s aptly named — the orchestra pit is big enough to host a gladiator’s killing spree.

Size is the main problem for this production, which has fabulous singing and dancing, and an effervescent cast (the hilarious Michael Ball returns to the role of Edna and Lizzie Bea plays Tracy Turnblad). The cheap set looks like that of a bus-and-truck tour dropped onto a football field. You feel far away, no matter how good the seat and the tech lacks dazzle.

But I’ll be damned if the jubilant finale didn’t bring a tear to my eye. “You Can’t Stop The Beat” is a tremendous message for this special, scary moment in the West End and on Broadway, because it inadvertently says theater can’t be kept down and will always persevere.

Also, we’re all sick of saying “the show must go on.”