Theatre binge-watching: how long could you sit in a theatre?

The eyes have it: Richard McCabe (centre) with the cast of Imperium

Another two-part stage play has opened in the West End, just down the road from the Harry Potter double bill. But how long could you sit in a theatre - and is theatrical binge-watching here to stay?

Seven hours is a long time to sit anywhere, not least in a West End theatre with limited legroom.

Yet that didn't stop around 900 ticket holders filling London's Gielgud Theatre on Saturday for a double helping of ancient Roman drama.

Comprising six one-act plays divided into two halves, the Royal Shakespeare Company's Imperium plays can be seen and enjoyed separately as independent thrillers.

Many theatregoers, however, are opting to see them both in the same day in a West End where productions of this sort offer the theatrical equivalent of a Netflix binge-watch.

Imperium charts three decades in the life of Cicero, a lawyer and orator who had a ringside seat on the rise of Caesar and the decline of the Roman republic.

Et tu, Brute? Peter De Jersey plays Julius Caesar

Based on Robert Harris's best-selling Cicero trilogy, the two plays - Conspirator and Dictator - are replete with political intrigue, alliances, betrayals and assassinations.

Richard McCabe, who won an Olivier for playing Harold Wilson in The Audience, plays Cicero, a wily character who is both respected and resented for his oratorical skills.

The Telegraph describes his performance as "a Wimbledon men's final five-set triumph of mental and physical stamina", while The Times simply calls him "magnificent".

Mike Poulton is the man who took on the Herculean task of distilling Harris's hefty tomes into one two-part opus.

The 71-year-old has experience in this area, having previously adapted Hilary Mantel's Wolf Hall and Bring Up the Bodies for the RSC.

"People like an epic," he told the BBC on Saturday. "It's sort of an addictive, box set experience.

"There is a certain amount of pleasure taken from absorbing ourselves in a period of history that is so similar to our own.

Living by the sword: Joe Dixon (centre) as Mark Antony

"It's fascinating to watch politicians make the same mistakes a couple of thousand years ago that the people around us are making today," he continued.

"During rehearsals, one of the actors said he would go home, turn on the news and see everything he'd been rehearsing for real."

First presented in Stratford-upon-Avon last year, Imperium - named after the Latin word for power - is far from the only two-part offering in London this year.

Just down the road, Harry Potter and the Cursed Child continues to pull in the crowds with its own two-part continuation of JK Rowling's magical saga.

Later this year, Matthew Lopez's two-part play The Inheritance transfers to the Noel Coward theatre following a sell-out run at the Young Vic.

On Broadway, meanwhile, the National Theatre's revival of Tony Kushner's Angels in America is coming to the end of an epic run that has seen it win two Oliviers and three Tonys.

Andrew Garfield won a Tony last month for his Angels in America performance

Poulton said he would love Imperium to follow Angels in America to the US, where he is certain its portrait of a republic tottering towards tyranny will be appreciated.

"I'd love this production to go to Washington," he revealed. "The people there would come and see this is the terrible direction we're heading unless we pull back from the brink."

For those without the stomach or the patience for an all-day theatre marathon, however, there are plenty of more manageable alternatives.

Faced with a two-week hole in its schedule last month, the Old Vic invited Sherlock's Andrew Scott to revive his one-man show Sea Wall - a monologue clocking in at a mere 30 minutes.

The likes of Imperium and The Inheritance, meanwhile, do not come close to rivalling some of the theatrical behemoths of yesteryear.

The RSC's legendary adaptation of Nicholas Nickleby lasted eight-and-a-half hours when it opened in 1980, while theatre maverick Ken Campbell once staged a piece called The Warp that lasted 22.

Imperium Parts I & II run in tandem at the Gielgud until 8 September.