Arthur is the culprit. When questioned by the police, he confesses and after his arrest he becomes severely morose, withdrawn and depressed. This culminates in Arthur finally having a nervous breakdown on Christmas Day and smashing his living room in a violent rage. By early 1987, Arthur has become so despondent that he is admitted to hospital. He returns the following spring to stand trial for the theft of the Christmas Club money. Despite Arthur having the whole community behind him, he is sent to prison for 28 days. After his release, he makes things worse by borrowing money from a loan shark. Mark returns in 1990 and announces on Christmas Day the following year that he is HIV positive. Arthur has a difficult time accepting his son's illness and his lack of education concerning HIV leads him to react in trepidation. Mark eventually helps him come to terms with his status, and he and Arthur enjoy a close relationship in the following years. In 1991, Arthur starts his own gardening business and is awarded a contract to maintain the Albert Square gardens. This leads to Arthur being employed by lonely divorcee Christine Hewitt (Elizabeth Power). Christine and Arthur soon become friends and Christine becomes Arthur's assistant. In May, Pauline goes to New Zealand to care for her brother, Kenny (Michael Attwell), who has been in a car accident. In Pauline's absence, Christine becomes a regular visitor to Albert Square and becomes very fond of Arthur. By Christmas, Arthur and Christine embark on an affair. Christine begins to crave more commitment and when he refuses, she gets a job at Kathy Beale's (Gillian Taylforth) café so she can be as close to him. The affair continues until Kathy sees them kissing and forces a confession from Christine. Faced with the threat that Pauline may find out, Arthur begins to cool their romance. Christine, sensing that she is losing Arthur, becomes emotionally erratic and begins to drink heavily, stalks Arthur around the square and attempts to buy the affections of his youngest son, Martin. This only infuriates Arthur. As a last resort Christine threatens to tell Pauline, unless Arthur tells her about their affair. Arthur finally admits the truth to Pauline, but tells her that he wants her and not Christine. Hurt, embarrassed, and angry, Pauline responds by hitting Arthur in the face with a frying pan, throwing a television set