Andrew Lloyd Webber has postponed the opening night of Cinderella at the Gillian Lynne Theatre.
In a statement Lloyd Webber said: "Today, on this "Freedom Day", I have been forced to take the heart-breaking decision not to open my Cinderella.
"At Cinderella, from the outset, we have employed a rigorous testing system for all the cast and backstage crew before they begin work. On Saturday, as part of this process, we identified one positive case in a member of our cast who has a cameo role in the show. As a precautionary measure, we cancelled two shows on Saturday while we carried out further tests on everyone backstage, which were negative. Any of those who were identified as a close contact of the positive case were given additional PCR tests. These tests too were negative. This morning we carried out additional tests on those due to perform tonight. Every one of them was negative.
"Despite this, the impossible conditions created by the blunt instrument that is the Government's isolation guidance, mean that we cannot continue. We have been forced into a devastating decision which will affect the lives and livelihoods of hundreds of people and disappoint the thousands who have booked to see the show.
"Cinderella was ready to go. My sadness for our cast and crew, our loyal audience and the industry I have been fighting for is impossible to put into words.
"Freedom Day has turned into closure day."
New dates for opening are to be revealed. Yesterday, Kenneth Branagh cancelled the entire run of his production of The Browning Version, due to non-availability of cast members during a limited rehearsal period.
Star Carrie Hope Fletcher added in a social media post: "Belleville will open its gates eventually…just not today." A Lloyd Webber spokesperson added: "It's hard to see a route forward under the current rules, but we will do everything we can to come back as soon as possible!" Further announcements are expected in the coming days.
Affected ticket holders have been told they will be notified about rescheduled tickets in due course.
Appearing in the world premiere of Cinderella are Fletcher in the titular role, alongside Ivano Turco as Prince Sebastian, Victoria Hamilton-Barritt as the Stepmother, Caleb Roberts as Prince Charming, Rebecca Trehearn as the Queen, Laura Baldwin and Georgina Castle as the Stepsisters and Gloria Onitiri as the Godmother.
Also in the show are Georgina Onuorah as the Ensemble / Alternate Cinderella, Sam Robinson as Dorian, Giovanni Spano as Gawain and Vinny Coyle as Arthur.
The full company includes Michael Afemaré, Lydia Bannister, Michelle Bishop, William Bozier, Lauren Byrne, Sophie Camble, Tobias Charles, Nicole Deon, Jonathan David Dudley, Dominic Adam Griffin, Michael Hamway, James Lee Harris, Leah Harris, Kate Ivory Jordan, Kelsie-Rae Marshall, Andy Rees, Alexandra Waite Roberts, Lauren Stroud, Georgia Tapp, Matthieu Vinetot and Rodney Vubya.
Fennell recently won an Oscar for her Promising Young Woman screenplay, and is part of a creative team led by director Laurence Connor. The production has choreography by JoAnn M Hunter, co-musical supervision by David Andrew Wilson and John Rigby, musical direction by Ben van Tienen, vocal coaching by Fiona McDougal, design by Gabriela Tylesova, sound design by Gareth Owen and lighting by Bruno Poet Casting is by David Grindrod Associates CDG.