Blowup

The plot is a day in the life of a glamorous fashion photographer, Thomas (Hemmings), inspired by the life of an actual "Swinging London" photographer, David Bailey.[9] After spending the night at a doss house where he has taken pictures for a book of art photos, Thomas is late for a photo shoot with Veruschka at his studio, which in turn makes him late for a shoot with other models later in the morning. He grows bored and walks off, leaving the models and production staff in the lurch. As he leaves the studio, two teenage girls who are aspiring models (Birkin and Hills) ask to speak with him, but the photographer drives off to look at an antiques shop. Wandering into Maryon Park, he takes photos of two lovers. The woman (Redgrave) is furious at being photographed. The photographer then meets his agent for lunch, and notices a man following him and looking into his car. Back at his studio, Redgrave arrives asking for the film, but he deliberately hands her a different roll. She in turn writes down a false telephone number to give to him. His many enlargements of the black and white film are grainy but seem to show a dead body in the grass and a killer lurking in the trees with a gun. He is disturbed by a knock on the door, but it is the two girls again, with whom he has a romp in his studio and falls asleep. Awakening, he finds they hope he will photograph them but he tells them to leave, saying, "Tomorrow! Tomorrow!"
As evening falls, the photographer goes back to the park and finds the body of a man, but he has not brought his camera and is scared off by a twig breaking, as if being stepped on. The photographer returns to his studio to find that all the negatives and prints are gone except for one very grainy blowup showing the body. After driving into town, he sees Redgrave and follows her into a club where The Yardbirds, featuring both Jimmy Page and Jeff Beck on guitar and Keith Relf on vocals, are seen performing the song "Stroll On." A buzz in Beck's amplifier angers him so much he smashes his guitar on stage, then throws its neck into the crowd, the photographer makes a grab for it as a souvenir. The photographer grabs the neck and runs out of the club before anyone can snatch it from him. Then he has second thoughts about it, throws it on the pavement and walks away. A passer-by picks up the neck and throws it back down, not realizing it's from Jeff Beck's guitar.[10]
At a drug-drenched party in a house on the Thames near central London, the photographer finds both Veruschka, who had told him that she was going to Paris â when confronted, she says she is in Paris â and his agent (Peter Bowles), whom he wants to bring to the park as a witness. However, the photographer cannot put across what he has photographed. Waking up in the house at sunrise, he goes back to the park alone and finds that the body is gone.
Befuddled, he watches a mimed tennis match, is drawn into it, picks up the imaginary ball and throws it back to the two players. While he watches the mime, the sound of the ball being played is heard. As the photographer watches this mimed match alone on the lawn, his image fades away, leaving only the grass as the film ends.

Question: Who writes down a false telephone number?
Answer: Redgrave