Brighton's Hippodrome remains top of the theatre buildings 'at-risk register' for the fifth year running, according to the Theatre's Trust.
Comedian and Theatres Trust trustee Dara O Briain launched the list at the Soho Theatre on Tuesday (January 23).
The Trust said the Middle Street theatre – which became a world heritage site in December 1985 – is ‘the UK’s most architecturally significant circus theatre - the finest surviving example of its type in the country.’
The Hippodrome opened as an ice skating rink in 1897, and theatre architect Frank Matcham converted the rink into a circus in 1901. The following year it was renovated into a theatre. In 1965 it became a bingo hall, until its closure in 2006.
Campaigners to save the theatre set up the Brighton Hippodrome Community Interest Company (CIC) in a bid to restore the Hippodrome to its former glory.
Controversial plans in 2014 to carve up the building as a multiplex cinema sparked a 16,500-signature petition to save the theatre.
The Our Brighton Hippodrome campaign, backed by DJ Fatboy Slim, set up Brighton Hippodrome CIC to develop a business plan and restoration strategy.
The local not-for-profit group has said it would welcome opportunities to collaborate on plans with the new owner.
But campaigners say the future of the Grade-II listed theatre continues to hang in the balance.
The freehold of the site was sold by Academy Music Group last November, to a newly-created company Hippodrome Investments Ltd, registered in Guernsey.
The Brighton Hippodrome CIC said so far the new owner has given no indication of its plans for the historic building.
A letter to city planners from the Theatres Trust said: "There is no doubt that restoration and reuse of the Hippodrome for live performance is the best outcome for the building.
"The focus of any future planning discussions for the Hippodrome should therefore ensure a scheme which will deliver full restoration as a live venue or, at the very least, ensure a scheme that would not preclude future reuse as a lyric theatre."