"What Lies Beneath" is the 1000th episode of Casualty and the 40th episode of the 30th series. It will air on 2 July 2016.

Series producer Erika Hossington revealed in an interview conducted by Digital Spy in 2015 that the 1000th episode would be special, as it will only be set in the hospital. She also revealed that an old face will reappear. In June 2016, it was announced that Cathy Shipton would reprise her role as Lisa "Duffy" Duffin for the 1000th episode onwards. Template:Series 30

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