Fifteen million tickets are sold each year for performances including top attractions such as The Phantom of the Opera, Les Miserables and Agatha Christie's The Mousetrap, a play that has been performed since 1952.

But the pandemic brought the curtain down on venues in March, leaving theaters facing an uncertain future where continued social distancing measures threaten their existence. 

Louis Hartshorn and Brian Hook, co-founders of Hartshorn-Hook Productions, are among the first to adapt to the new reality, announcing the reopening of an immersive adaptation of The Great Gatsby to open in October.

"The show will be reimagined as a masquerade ball," Hook told AFP. 

Spectators are invited to wear masks, which they can integrate into their disguise, and gloves if they wish.

The audience will also be reduced to 90, down from 240 previously, and the schedule has been changed to allow for thorough clean-ups.

The good news is that tickets are "selling and people want to come back", added Hook.

But Hartshorn admitted that "we have to do extremely well in order to break even because the numbers are against us".

Read also: Andrew Lloyd Webber launches free musical theater streaming service

Tourist trouble

Another immediate challenge is the lack of tourists, with hotels, restaurants and museums closed until at least early July.

The introduction on June 8 of a 14-day quarantine for most travelers arriving in the country has also tempered hopes of a swift recovery.

"Around a third of attendees in London theaters are overseas tourists... and for the moment of course there is very little prospect of having overseas visitors," Julian Bird, head of the UK Theatre lobby group, told a recent parliamentary committee. 

Up to 70 percent of theaters could go bankrupt by the end of the year, he warned. 

Immersive experiences

The current crisis has left a £3 billion ($3.7 billion, 3.3 billion euro) hole in theater revenues this year, a fall of more than 60 percent, according to a study by Oxford Economics for the Creative Industries Federation.

This estimate does not take into account the possible reluctance of the public to return when allowed, with the federation warning of 200,000 job cuts without government intervention. 

To survive, some theaters are offering alternative products.

At London's Old Vic Theatre, actors Claire Foy and Matt Smith, stars of the hit TV series The Crown, will perform the play Lungs without an audience, while keeping their distance. 

Each performance will be filmed and broadcast live to the 1,000 people who purchased tickets at the usual prices of between £10 and £65, although all will enjoy the same view. 

It's a bold gamble when many other theaters, such as the National Theatre in London, have posted free online performances of plays filmed before the pandemic. 

Shows that involve audience participation could be the big winners, according to Brian Hook.

"We were already on a boom for immersive theater before this crisis... I think now might be a very positive time for that," he said.

One Night Records will launch one such project in early October, taking ticket-holders on a journey through musical genres from the 1920s to the 1950s in a secret location called "Lockdown Town".

"Because the venue is so large and because immersive has this special gift -- which is territory, you know, space. That's why we're able to do it," One Night Records general manager Tim Wilson told AFP. 

But he, too, has had to adapt, selling tickets in groups of four and transforming the free stroll into a linear route.

Read also: Socially-distanced music venue to open in London

Performance anxiety

In the traditional world of theater, social distancing measures are a real headache.

With people having to remain two meters apart, under current rules, the Royal Shakespeare Company said it can only accommodate 20 percent of its usual audience.

"With the furlough scheme changing in nature over the coming months and then coming to an end, that's a moment of extreme vulnerability," Catherine Mallyon, executive director of the Stratford-upon-Avon based company told AFP. 

"And how would we do the performances with social distancing? Romeo and Juliet two meters apart, it's quite hard to imagine," she said.