BBC News
By Tim Stokes
image captionThe Lyceum Theatre with Waterloo Bridge in the background
For those in the theatre industry, the festive period would usually be one of the busiest times of the year with extra shows and people packing out venues.
Yet London s move into tier four means that the stages of the West End will remain silent this Christmas - as many have been since one particular day back in March. In the industry the 16th [of March] is now commonly referred to as Dark Monday . It was the night when all the theatres went dark, explains Troy David Johnston.