And Then There Were Two, originally transmitted on ITV, 5/9/1973

Chrissy confides to Jo that she thinks Robin is in love with her. Jo convinces Chrissy that it is not love, but lust.

Robin's friend Larry calls round. He and Robin are off to watch football. While Chrissy makes tea, Larry expresses his amazement and envy at Robin's living arrangements. Robin boastfully tells various untruths about his relationship with the two women, which Chrissy overhears. Embarrassed, Robin and Larry make a swift exit.

Chrissy is now convinced that Robin has erotic fantasies about them. Jo reminds her that she will be away the following Saturday night, leaving Chrissy alone with Robin.

Downstairs, landlords George and Mildred Roper bicker.

Some days later, Chrissy's anxiety intensifies when she finds Robin reading Quorum, a journal of personal relationships. Inspired by an article, he measures their heads to judge their virility; Chrissy is further convinced that he is obsessed by sex.

Jo asks Robin to reassure Chrissy that he will not attempt to ravish her. Instead Robin, enjoying the absurdity of the suggestion, plays upon her fears, pretending to be an ape.

On Saturday, Robin continues to tease Chrissy, before going to the pub.

Downstairs, George moans that it is indecent for Robin and Chrissy to be alone together. Mildred goes upstairs to escape George and chat with Chrissy.

Robin meets Larry, still boasting about his sexual power. As if in confirmation, he meets Liz, an acquaintance from his technical college. A strong mutual attraction is immediately apparent.

Robin takes Liz back to his flat. She mistakenly thinks he shares the property with another man. He does not disillusion her, making her wait outside while he tells Chrissy to go to her bedroom. She misunderstands, thinking that Robin is making a pass at her. He explains that he has a girl outside. Offended, Chrissy shuts herself in her room.

Installed on the sofa, Liz responds keenly to Robin's advances. Meanwhile, Chrissy telephones Jo. Amused by the evening's events, Jo suggests Robin must not fancy her after all. Her pride is hurt, Chrissy seeks revenge.

Robin and Liz are beginning to undress each other when Chrissy suddenly enters. She pretends to be pregnant with Robin's baby. Angrily, Liz leaves.

Robin is initially dismayed, but cheers himself up by chasing Chrissy around, pretending to be an ape. She shuts herself in her room. His good humour restored, Robin fills the kettle.