The West End will remain closed until at least 31 May, it has been confirmed by the Society of London Theatres (SOLT).
Other venues (including all ATG theatres across the UK) had previously extended their closure dates, but this blanket policy for all West End shows has now been confirmed.
SOLT said in a statement: "We are now cancelling all performances up until and including 31 May 2020 to help us process existing bookings whilst we wait for further clarity from the government in terms of when we will be able to reopen.
"We are so sorry that in these testing and difficult times you are not able to enjoy the show you have booked for and hope the following helps clarify next steps in respect of your tickets .
"There is nothing that you need to do if your performance has been cancelled, but we do ask for your patience.
"If you have booked directly with the theatre or show website for an affected performance, please be assured that they will contact you directly to arrange an exchange for a later date, a credit note/voucher or a refund. If you have booked via a ticket agent they will also be in contact with you directly."
The West End production of Leopoldstadt has confirmed its run will end early, with the planned National Theatre Live screening not going ahead as planned. However, the production has promised it will be returning later in the year.