Waters of the Moon

Experience quickly taught him, however, that he was better suited to the 'character' parts.

"The most unsuitable part I ever played was the romantic juvenile lead in Mr Pym Passes By, when I was in repertory at Salisbury," he remembers.

"It was one of those 'Who's for tennis?' parts. I was quite dreadful. I said to Reggie Salberg, the manager, 'Why did you cast me?' He said 'To prove you can't play juvenile leads'.

"I wasn't a handsome young man, so it was inevitable. It rankled for years, though."

For most of his career, the 69-year-old stage and TV actor has specialised in playing older character parts - more often than not the kind of fearsomely whiskered old coves who look like they'd be pretty handy with a blunderbuss.

True to form, his latest play, Waters of the Moon at Salisbury Playhouse, sees him a playing a retired colonel.

"They're all I can play, now I'm in my late 60s - lecherous soldiers and retired colonels. I was a retired brigadier in Foyle's War on TV the other week.

"Fortunately I love playing them. There aren't many older parts on TV now either, so you have to take what you can get."

Veteran of many a period drama, including the classic 1995 version of Pride and Prejudice, in which he played Sir William Lucas alongside a smouldering Colin Firth, Christopher should feel very much at home in Salisbury's revival of N C Hunter's forgotten 1951 classic - its first professional staging for more than 25 years.

"It's set in a run-down hotel on Dartmoor, where all these private residents are eking out their pensions, including my character, Colonel Selby," he explains.

"A car breaks down outside in the snow and this new family suddenly turns up, disturbing the equilibrium."

Playing at Salisbury is almost like coming home for Christopher. A member of the Playhouse company for two years in the early 60s, he was born in Trowbridge and educated at Lord Weymouth's Grammar School in Warminster.

It was at school that he launched his acting career with one of his greatest theatrical challenges.

"Maxence Macdonald, the headmaster's wife, picked me for this play, Murder in the Cathedral.

"She said 'Benjamin, take this home and learn it over the holidays'. I had a huge speech that was eight pages long, but I learned it and it was a great experience.

"She was a very inspiring person. She only died last year, but we always kept in touch and she tried to see everything I did. It almost feels like I haven't got anyone to please now."

Christopher, who is married with three grown-up children, was the only actor in his family.

"My father had a music shop in Trowbridge and later bought my grandfather's farm. From the age of 12 I lived on the farm, but I didn't like having to get up at 4am and help my brother drag a calf out of its mother's womb."

If Christopher is recognised today, it's invariably for one of his many roles in cult British TV.

In the 60s and 70s he made a host of guest appearances in shows such as The Avengers, The Prisoner and Doctor Who - perfect vehicles for his larger-than-life performances.

In Doctor Who, he worked alongside Jon Pertwee and Tom Baker on two of the classic sci-fi series' most memorable stories.

Undiluted fan worship and requests to record DVD commentaries means Christopher hasn't been allowed to forget his association with the show - to his great pleasure.

"I think it's very touching. It was great fun working with Tom Baker. He was a most generous actor and made the whole thing very amusing."

Even on the other side of the world, Christopher finds himself under siege by fans.

"I spent a lot of time with the RSC doing good, solid work, and I was playing Dogberry in Much Ado About Nothing.

"We took it to an arts festival in LA in 1984. After the first night there were people from the Doctor Who Appreciation Society queuing up at the stage door and asking for my autograph."

With the announcement of a new series of Doctor Who, would Christopher fancy a turn as the legendary Time Lord - not a million miles from some of the borderline eccentrics he has played?

"I'm afraid I'm far too old. I would have loved to have played him years ago, but I wouldn't dream of it now."

Waters of the Moon is at Salisbury Playhouse from January 22 until February 7. Tickets cost from £8.50. Box office: 01722 320333.