Ten new arts venues have been added to the Theatre Buildings at Risk register this year, including the Brighton, Derby and Dudley Hippodromes, the Swansea Palace and the Coronet in London.
The annual report, which is published by the national advisory body for theatres The Theatres Trust, acts as a means of watching, managing and supporting the UK's most vulnerable theatres.
A total of 48 theatres feature on the current list, down slightly from the 49 on the register last year. This year the Risk Values associated with each theatre have also been published; types of risk looked at include lack of funding and high maintenance costs, threat of demolition and local development adversely affecting the theatre.
Nine theatres across the UK have been given the highest Risk Value of six, including the Grade II listed Swansea Palace, Brighton Hippodrome and Alexandra Palace Theatre in London. These buildings are described as being either in a "critical physical condition" or due to be "irrevocably altered or demolished".
Penelope Keith, trustee of The Theatres Trust said that more needs to be done to protect theatres under threat, and described plans for the cinema conversion of the Brighton Hippodrome as "heritage destruction".
New additions to the register this year include the Coronet in London and the former Theatre Royal in Manchester, which are on sites marked for redevelopment. Others added include the Forest Theatre in Berry Hill and The Brewhouse in Taunton.
Four theatres have been lost forever as their local authorities have determined they are no longer to be classed as theatres. These include St Peters Theatre, Southsea and the Cochrane Theatre in London. The land that these buildings occupy will be redeveloped.
There is some good news to report, with seven theatres being removed from the list as their future is secure. Three of these are in Scotland, including the Britannia Panopticon in Glasgow, which received funding for repairs. Four of the buildings that have been saved are in England, including Margate's Theatre Royal, and the Floral Hall in Hornsea - this was used by the Theatres Trust as an example of what can be achieved "when a community comes together to campaign to save their local theatre".
Director of The Theatres Trust Mhora Samuel said: "We are at risk of losing really important and historic theatre buildings as a result of neglect, development and demolition. It's so sad to see theatres treated in this way".
Click here to read the full report.