It was spending a weekend as the house guest of an actor so full of his own self-importance he could barely see straight that inspired Noel Coward to write his classic comedy of manners.

Hay Fever is set in the country home of the eccentric Bliss family. Judith Bliss is a recently-retired stage actress who can't let go of the limelight and her husband David is a self-absorbed novelist. When they and their two bohemian children invite an assortment of guests for the weekend, the result is pandemonium of the Noel Coward variety.

Christopher Timothy, who plays David Bliss, is enjoying watching the play as much as being in it. "There's some great banter between Judith in the children, but I'm not involved with all that. David likes to think of himself as a quiet observer, the truth is he never really knows what to do," says Christopher, who stars opposite Stephanie Beacham in the production, on tour following a hit West End run.

The play sends up the hedonistic aristocracy of the between-the-wars period when rich families had little else to do other than bicker and wallow in self-delusion.

The Blisses exist in their own little bubble where the boundaries between reality and fiction are blurred. Thrown into wildly melodramatic situations by their hosts, the beleagured house guests reach the conclusion that they're in the company of a family of lunatics and leave at haste. The Blisses remain oblivious to their departure.

"They're spoilt and privileged, they play silly games and flirt with their guests, but that's just how they are. Despite the bickering, there's no doubt that David and Judith love each other," says Christopher. "Coward wasn't presenting any kind of moral in this play, we're not supposed to learn anything from it. We just squirm with embarrassment and laugh at how the family behaves."

One of the play's more cringe-worthy moments is when the family hold an after-dinner Charades-like game of Adverbs' and get impatient with the other guests who can't keep up - because, frankly, they're bemused and aghast at the theatrical self-indulgence. For the Blisses the game is full of sparkling quips, but the guests are out of their league when it comes to acerbic put-downs.

"Ooh, that scene makes your toes curl," laughs Christopher. "Coward based the play on a weekend he spent at an actor's home, he was sending up the larger-than-life theatrical types like Judith that I suppose he knew and worked with. Stephanie Beacham does a fantastic performance as Judith, I'm lucky to be working with such a great team. I'm very much a team-player."

This is Christopher's first Noel Coward role and he says it's not as easy as it looks. "It has to be done in a very specific way because it epitomises a particular period and kind of humour. I wasn't around then but I remember my grandparents talking with those clipped tones," he says. "It's demanding because everything is in the dialogue. It's a comedy of manners - well, bad manners - which doesn't apply to us now but nothing is funny unless it's believable, so you have to try to capture the reality in a situation."

Christopher has had a long career TV and theatre but is still best known for playing country vet James Herriot in All Creatures Great And Small, set and filmed in the Yorkshire Dales 30 years ago. He's looking forward to appearing in Bradford, so he can visit the Dales again. "I have extremely fond memories of that show, it turned my life around," he says. "I'd never read any Herriot books, I didn't think I'd be interested in them, but whenever you went on a bus or a train you'd see someone reading one. They were so popular I knew the series would be a hit. I bet Yorkshire Television spent a long time kicking themselves because they turned it down!"

There isn't much on telly to match it these days and Christopher winces when asked what he thinks about the state of British TV today. "I think television drama is in great danger," he says. "It seems to be striving for mediocrity or to simply offend. You have to take risks and push boundaries but you must also remember it's our job to delight and entertain."

He's seldom been off our screens since his James Herriot days, most recently starring in BBC1 medical soap Doctors Dr Mac' MacGuire. "You work hard on a show like that because it's so fast, you need a good director to help get it right quickly," says Christopher.

He directed several episodes himself and would like to do more directing. "In the deep, dark recesses of my mind I want to direct movies so I approached it as if I was directing a movie," he says. "I'd never directed before but I've always been fascinated by sets and camera angles and I picked up a lot over the years.

"Now I see things through a director's eye, I'm walking down a street right now and I've just noticed a lovely little alleyway, that would make a great shot. My wife's the same, she's a painter and sees everything from an aesthetic viewpoint."

Hay Fever runs at the Alhambra from May 14-19. For tickets ring (01274) 432000.