By Neil Smith BBC News Online

Bonneville's films include Stage Beauty and Notting Hill

"Literally, it's Latin for sewer," explains actor Hugh Bonneville. "And in biology it refers to the back end of various animals."

He's talking about Cloaca, the curious title of the first production in Hollywood actor Kevin Spacey's first season as artistic director of London's historic Old Vic theatre.

If you are wondering how to pronounce it, it's "klo-ack-ar". In the context of the play, however, it means something else entirely.

"It really refers to the slurry and effluent of life," says the 40-year-old star of Iris and TV's Love Again.

"It's a catchphrase that the characters have used all their lives without really knowing what it means."

'Best director'

Spacey is best known for his screen roles and will act in two plays at the Old Vic next year.

However, he chose to direct Cloaca rather than take one of the four male roles himself.

Bonneville (second left) with the rest of the Cloaca cast

Bonneville describes Spacey as "probably the best director I've ever worked with".

"I'm not being gushy," he continues. "His understanding of how an actor's brain works is exciting.

"Very few directors get inside an actor's head the way he does."

And Bonneville has nothing but admiration for Spacey's plans for the historic South London venue.

"He's passionate about the play, the building, about acting - about theatre full stop."

Ambition

In Cloaca, Bonneville plays a self-serving politician who is not afraid to sell a friend down the river if it means career advancement.

But while Peter Mandelson and Tony Blair's names are mentioned in the show's glossy programme, the actor says he did not base his performance on anyone in particular.

Bonneville's co-stars include Peak Practice star Adrian Lukis

"I'm not doing an impression, but I recognise in the character's ruthless ambition certain politicians of our great nation," he admits.

"A lot of politicians are more keen on promotion and access to power than actual ideology.

"I don't believe you get to the top of politics without trampling on people."

Written by Dutch playwright Maria Goos - a name as unfamiliar to British audiences as the curious title of her play - Cloaca tells of four college friends who are reunited in their 40s.

They range from a homosexual bureaucrat (Stephen Tompkinson) to a drug-abusing lawyer (Adrian Lukis) and a philandering theatre director (Neil Pearson).

The catalyst in the piece is one character's misappropriation of public artworks he has sold to finance his lavish lifestyle.

Unknown

Theatregoers will see similarities between Cloaca and the long-running West End hit Art, which also dealt with male relationships placed under strain.

Coincidentally, Art was also written by a relatively unknown female writer hailing from Europe - Yasmina Reza.

Spacey became artistic director of the Old Vic in February 2003

Bonneville, however, is quick to deny any connection between the two.

"It's a fairly lazy comparison to be honest," he says dismissively.

"Yes, there are similarities, but the themes are darker and richer and more painful than in Art.

"It's a very different beast that takes you in a different direction."

The production has already made headlines thanks to Spacey's comments last week attacking audiences who allow their mobile phones to ring at the theatre.

Bonneville believes too much has been made of his director's remarks, but he still agrees wholeheartedly with his sentiments.

"We're used to sitting in our living rooms shouting at the telly, so sometimes when we go out to a public event we forget basic decent courtesy.

"I'm all for the audience being as vocal as they like, but I think a few basic ground rules aren't draconian."

'Passion'

The actor's role in Cloaca follows a series of well-received performances on film and television, often playing real-life figures.

In the last few years he's played architect Christopher Wren, poet Philip Larkin and academic John Bayley, the widower of novelist Iris Murdoch.

Most recently he was cast in the film Stage Beauty as diarist Samuel Pepys, a literary figure for whom he says he's "always had a passion".

Bonneville played Philip Larkin in the 2003 BBC drama Love Again

"I would hate to do a stitch-up job on a living person, but when you have scripts of the quality of Iris and Love Again I don't think you're doing a disservice to anyone involved," he says.

However, he does acknowledge that if he does not exercise caution, he may be in danger of becoming typecast.

"Having played Larkin and John Bayley, I'd better stop playing bald, stammering academics!"

Future projects include playing a psychiatrist in a film of Patrick McGrath's novel Asylum and a 19th Century anthropologist on the trail of pygmies in the French-South African co-production Man to Man.

In the meantime, however, Bonneville says he is excited to be part of the latest chapter in the Old Vic theatre's prestigious history.

"It's a real honour to be part of a new journey," he says.

"Quite honestly, it's the best time I've ever had with my clothes on!"