text: Wednesday's matinee was curtailed before that evening's show was called off completely.
  Ticket holders for both shows will be offered refunds, a show representative has confirmed.
  Thursday's performance will go ahead as scheduled at London's Cambridge Theatre, it has since been announced.
  An audience member at Wednesday's matinee told the BBC the show was stopped after approximately 30 minutes.
  A representative for the theatre then came on stage and said the actress playing Matilda was unable to sing the rest of the songs, so would speak the lyrics instead.
  The show's interval was then extended by around 15 minutes.
  At the end of the interval, the theatre representative returned and said the actress's voice had deteriorated further and that the performance would be cut short.
  The rest of the cast then performed three songs from the second half of the show while a member of the production team narrated the story.
  One audience member who was at Wednesday's matinee said the afternoon had left her "genuinely gutted".
  She continued: "Â£75 a ticket is not cheap, and not having a healthy understudy for that price is unacceptable."
  "Obviously we were disappointed not to see the whole show," tweeted Debbie Stoddart, another member of the audience.
  "But it was evident from the first song that Matilda wasn't well so it was the right thing to stop the show.
  "The most important thing is the well-being of the cast, specifically the younger ones."
  The Royal Shakespeare Company's production is based on Roald Dahl's popular children's novel.
  It was adapted for the stage by playwright Dennis Kelly, with music and lyrics by Tim Minchin.
  The show became a huge box office success when it opened in London's West End in 2011.
  The following year the production won seven Oliviers, a record at the time. It later transferred to Broadway.
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target: One performance of West End musical Matilda was cancelled and another cut short after several members of its cast and their understudies became ill.