This is part of the She’s So Giallo (Women of 1970s Italian Thrillers) season at the Barbican curated by Josh Saco, aka Cigarette Burns Cinema. You can find all the details here.
Cigarette Burns introduction:
Lost for nearly 30 years and regarded as Dario Argento’s masterpiece, Michael Brandon and Mimsy Farmer star in this rarely seen cult horror. Roberto (Brandon), a drummer in a rock band, finds himself embroiled in a nightmare when he is framed for killing a mysterious man who has been stalking him. But Roberto’s troubles get worse when he’s blackmailed by an unknown killer who is knocking off his friends, one by one. Turning to his wife, Nina (Farmer), Roberto struggles to identify who he can really trust. Featuring a playful score by Ennio Morricone’s and innovative cinematography from Franco Di Giacomo, this suspense-filled drama has rightly cemented itself as one of Argento's greatest giallo features.
Here (and above) is the trailer.