Producer’s Workshop. Mrs Floyd will not take the call.
The last forty seconds of Young Lust are not a skit written in a studio booth. In the autumn of 1979, at Producers Workshop in Los Angeles, engineer James Guthrie put a telephone in a soundproof corner and recorded an extension onto quarter-inch tape. He had already called his neighbour in London, Chris Fitzmorris, who had the keys to Guthrie’s flat. The instruction was simple: pick up, say hello, let the operator speak, hang up. Do it as many times as the call comes. The first operators were too brisk. The third one stayed on the record.
She was not told she was being recorded. Guthrie asked for a collect call to Mrs Floyd, from Mr Floyd. Fitzmorris answered, then hung up, again and again, until the operator started to worry that a man was in the house and the wife was not taking the call. Afterwards Guthrie edited his own voice off the tape and left hers, and Fitzmorris saying hello. The beeps under the dialogue are ordinary transatlantic signalling of 1979. On the album they are how Pink, on tour, learns that someone else is at home.
The song in front of that call is a hard-rock joke with a straight face. Waters and Gilmour wrote it. Gilmour sings it. The riff is stadium cock-rock, the lyric a groupie circuit: a new boy, a dirty woman, a desert town. It sits on The Wall after Empty Spaces and slams into One of My Turns, which is the hotel room after the hang-up. Harvest released the album in Britain on 30 November 1979. Columbia followed on 8 December. The album cut runs 3:25. An Italian single used a longer edit, about 3:56. Britain did not get Young Lust as the A-side. The single, out on 23 November, was Another Brick in the Wall, Part 2, with One of My Turns on the back.
I told her that I wanted to make a collect call to Mrs Floyd. “Who’s calling?” she asked. “Mr Floyd,” I replied. Chris’s timing was terrific. Over and over he would hang up just at the right moment and she became genuinely concerned. “Is there supposed to be someone there besides your wife?” … Unwittingly, she was helping to tell the story.
(James Guthrie, on the Young Lust phone call, 1979)

On The Wall tour in 1980 and 1981 the number is the rock-star costume: the surrogate band up front, the real band behind the bricks, a song about wanting a dirty woman that ends with a man hanging up. The riff is the joke. The operator is not. She thought she was placing a call for someone whose wife would not accept the charges, and she kept trying.
Guthrie said later that he sometimes wondered if she ever heard herself on the record. The album does not name her. It does not need to. Young Lust is three minutes of cheap desire, and then a real woman in a headset, in 1979, doing her job, and telling the story by accident. The joke only works because the 1977 tour had already made the groupie circuit feel like a job, and Waters was done pretending he liked it.