Alison Light’s recent book, 'Mrs Woolf and the Servants', showed how live-in help can be a mixed blessing. Illona Linthwaite’s excellent revival of 'My Sister in This House' is closer in tone to Jean Genet’s 'The Maids' (1948), both based on the real-life murder in France of a mother and daughter by sisters in 1933. Kesselman’s award-winning 1981 version shows how social division, religious guilt and a claustrophobic ambience can converge to produce fatal results.