Ultimately, Miss Saigon has two themes: the pity of war – any war – and motherhood. It is the emphasis on motherhood that differentiates it from Madame Butterfly, where the presence of Butterfly’s son seems almost irrelevant to her torment when she discovers she has been betrayed by her American husband. For Kim her son is her raison d’être. ‘From the day she has this child she becomes a completely different person,’ Boublil says. Her obsession with her child becoming an American citizen is thoroughly plausible in the context of the fate of the abandoned offspring of American soldiers and Vietnamese mothers. Archive footage of the bui doi, which means ‘dust of life’ in Vietnamese – the vilified ‘half-breed brats’, as the Engineer calls them – in rows of cots in orphanages is shown in the second act, and gives the story a genuine sense of potency. Boublil and Schönberg’s frequently repeated musical themes and direct, unvarnished lyrics may not be to everyone’s taste but the emotion of the piece is hard to avoid. ‘Even Les Mis, which is an extraordinary emotional tour de force, doesn’t cut you like a dagger in the way that Miss Saigon does,’ Mackintosh says.