The Royal Opera House’s upcoming production of Puccini’s Tosca includes eight trigger warnings concerning themes such as murder, sexual assault, and torture, reflecting modern Theatreland’s approach.

While these warnings are common, an unusual alert has been issued: the audience is being warned about the venue’s curtain-up bell.

Described as ‘loud and startling,’ the bell’s intent is to remind patrons there are ten minutes left before the show starts, prompting them to wrap up their bar visits.

The only person who might find this surprising was Del Boy from an Only Fools And Horses Christmas special in 1986, where he confuses the bell at Theatre Royal, Drury Lane during Carmen for a call for last orders.

In the scene, Del Boy, portrayed by David Jason, humorously comments, ‘Cor blimey! He’s rung that one early, ain’t he!’ upon hearing the bell.

Opera buffs at the London venue spotted that performances come with advance warnings. 

The online announcement for the upcoming show notes: ‘The bell is loud and can be startling. It is rung ten minutes before the show starts and at each interval.’

It is understood the Royal Opera House (ROH) has put the warning on shows including Aida, Romeo And Juliet and Carmen.

 The West End has been criticised for its deference to those of a sensitive disposition in recent years, with shows accompanied by content warnings, even where audiences know the plot covers themes such as suicide, mental illness and death.

Last year the West End adaptation of Stanley Kubrick’s satirical anti-war film Dr Strangelove warned audiences the play involved cigarette smoking, replica guns and bad language.

The Royal Shakespeare Company felt the need to stress that its rendition of The Merry Wives Of Windsor contained ‘body-shaming’, in reference to character Sir John Falstaff, also known in the Bard’s works as ‘the fat knight’.

And those attending Slave Play, starring Kit Harrington, were offered ‘self-care’ tips and breathing exercises to cope with sexually explicit elements of the plot which focused on three interracial couples in relationship counselling. 

But the ROH is believed to be the first to point out the frightening aspect of the curtain-up bell.

 Lord Young, Free Speech Union founder, said: ‘You would have thought people triggered by loud noises wouldn’t be opera lovers. What are they supposed to do when the sopranos hit the high notes? Cover their ears?’

An ROH spokesman said: ‘This is not a trigger warning. The information… is on our accessibility page.’

It comes as the ROH’s planned month-long run of Tosca has been mired in controversy over the decision to cast Russian soprano Anna Netrebko in the title role despite her homeland’s ongoing invasion of Ukraine.

Netrebko is a long-term supporter of Russia’s president Vladimir Putin, and previously won a payout from New York’s Metropolitan Opera after it cancelled her performances when she refused to denounce the despot.