Off-screen, she struggled with heroin addiction for around 20 years and died alone in the bedroom of her sheltered accommodation in Stoke Newington, London - aged 70 - on 7 April.
The other characters couldn't stand him: the local doctor complained bitterly about the mess Willy made on the pavements, and owner Ethel had to decline two marriage proposals when her suitors asked her to get rid of her precious pet.
Welsh felt using real horses in the film was understandable, but argued the outdoor scenes infringed on the "abstract theatrical design" that gave the play its creativity.