Magicians never reveal their secrets. But sometimes, they admit they were wrong.

On Thursday night in London, members of a top British magic society came together to right a three-decade-old blunder: The rejection of what they now consider one of the greatest deception acts their members ever fell for.

“It was an amazing ruse — fooling a room full of magicians,” said Maddie Spencer, 48, who is in the group, known as the Magic Circle.

In March 1991, when the club was restricted to men, a woman named Sophie Lloyd disguised herself as a man and earned full membership. (Her alias: “Raymond Lloyd.”) But when she and her accomplice revealed their ruse later that year — at the same time as the Circle started accepting women — the society promptly ousted her.

For years, “Raymond” was like a ghost floating through the Circle; a rumor or a half-formed memory. Then, in November last year, the Circle announced a public search for Ms. Lloyd. They wanted to apologize and welcome her back.

On Thursday night, they took a step toward righting the wrong.

Being magicians, any old “sorry” would not do. They needed a performance worthy of such a daring deception.