From “What Happens After That,” a New Yorker article about Alfred Hitchcock, written by Russell Maloney and dated 9.2.38:

“Whether he works in Hollywood or England, Hitchcock will go on making his own kind of picture. His mind is full of plans; nothing else can get in. When he was last in New York he wasn’t half so concerned about his financial negotiations as about a story idea he had.

“‘The picture would open near the London docks, at dawn,’ he explained. ‘The police are chasing a lascar sailor down a grain elevator. He gets away from them, runs through the gates into the road, and finally hides in a sailors’ boarding house. The police catch up with him, and he escapes from them again. The chase goes through the Sunday morning market in Middlesex Street.

“At last the lascar comes to St. Paul’s Cathedral and runs in, with the police after him. There’s a service going on, so he runs upstairs to the balcony that goes around the dome. Just as he reaches the top step he falls over the railing down into the nave, dead, with a knife in his back. Some of the congregation rush up and turn him over. One of them touches his face and a smudge of blacking comes off. The man isn’t a lascar at all — he’s just made up as one.”

“At this point in his recitation Hitchcock became subdued. Then he said, ‘It’s good so far. But what happens after that? I wish I knew.'”