TELEVISION reporter Luke Casey knew, before the first episode was filmed, that the Dales Diary would be a hit with viewers.

Now, as the weekly half-hour countryside ramble prepares for its 12th series, he is already planning for a 13th.

"Its strength is in its gentleness," says 60-year-old Mr Casey, with a hint of his native Irish accent. "It is very, very relaxing, an easy watch for half an hour with your feet up and a cup of tea."

The formula resulted in sky high ratings for all 11 series so far, with Tyne-Tees officials celebrating capturing on average more than 25pc of the available television audience.

A survey by Yorkshire Television, which also screens the Diary, discovered viewer appreciation of the series was one of the highest ever. Not only were a high percentage of households turning it on, but most were thoroughly enjoying it.

Mr Casey was a reporter for the BBC's Nationwide news programme when a friend working for a TV production company approached him with an idea for a gentle countryside documentary series.

"I was already getting out and about very much with Nationwide - walking across Scotland and that sort of thing," he remembers. "I just knew we had something special in the dales, the moors and the hills in the North of England and we threw some ideas about.

"I had a good feeling about it right from the beginning. I felt there really was a niche for this kind of programme. The countryside is one of the greatest assets but it was largely being ignored by television, apart from a few fictional things like Emmerdale."

The programme takes Mr Casey, who lives between Darlington and Stockton, and his camera crew from the Pennines to the East Coast and from the Scottish borders to the West Yorkshire dales.

"I absolutely love hill country and I love the people up there," he says. He recalls meeting upper Swaledale farmer Jim Alderson several series ago. "He was a big, raw-boned man who had lived in a remote spot all his life and didn't suffer fools gladly. He had that fierce streak of independence that many upper dales people had.

"But what absolutely impressed me was when he went to see his new- born lambs and handled them so gently with almost tears in his eyes. He referred to their birth as the annual miracle. That encapsulates the area and the deep passion people have for their stock and their place."

Ideas for items come from a wide range of sources, not least the columns of the Darlington & Stockton Times. "I always read the D&S - it's the happy hunting ground for me," says Mr Casey, who joined the D&S' sister paper, The Northern Echo, in 1959 and was one of the papers' first John North columnists.

As the momentum of the Diary gathered, more and more people began to contact the production team with ideas for features.

"It's lovely that dales folk regard it as their own programme. I decided a long time ago that the series would have a kind of integrity.

"The countryside was often portrayed on television, particularly by big town and city programme makers, with rather a country yokel image and I always found that highly offensive. I was determined not to patronise country people."

Pubs, too, are a fine source of inspiration for Diary items. "I have got the accounts department convinced that pubs are absolutely necessary - purely in the interests of research, of course," he laughs.

Almost as big a star as Mr Casey himself is his ash walking stick, which accompanies him on his travels.

"I think the stick is more recognisable than me," he says. "I have a lot of sticks, but I have had this one for about 30 years. I bought it at a game fair and liked it because it is a single piece of ash. It has been round the clock a bit - like myself!"

Mr Casey is acutely aware that it is not only country dwellers who are regular fans of the Diary. "The programme wouldn't survive without the huge numbers of town and city people who watch it and love it. There's a lot of interest from townsfolk in seeing how people have moved from the city to the country and perhaps set up a business or craft workshop.

"I'm sure we have been responsible for a lot of people upping sticks and deciding to leave the rat race."

When he's not filming, Mr Casey likes to stride out for a "real" walk. "A lot of the programme involves walking, but it is TV walking, where you are repeating something over and over again for the camera," he explains.

He recalls a decision, when filming at Hutton le Hole on the North York Moors several years ago, when he opted to walk over to Farndale.

"The weather came in very bad - horizontal rain, sleet, everything - and I was bent double into the blizzard when a car passed me, stopped and reversed. I thought they were going to give me a lift, but the window lowered about an inch, a tiny scrap of paper was pushed out and a voice said: 'Would you sign an autograph, please, Luke?' I signed the soggy piece of paper and pushed it and the pen back through the window and the car drove off. I was quite flattered that they considered me so robust that I didn't want a lift."

While he will give little away about the new series, which begins on Tyne-Tees and Yorkshire on Tuesday at 7.30, Mr Casey is pleased to have finally had the chance to include a profile of actor Ian Carmichael, who lives on the North York Moors.

"I'd wanted to do something on him for a long time. He is Yorkshire-born, which might surprise people who associate him with playing the posh, landed, southern country gent. He came back to retire 30 years ago but is still working."

The history of Coverdale also features in one episode.

Mr Casey is in no doubt that the Diary will go on for many, many more years, providing the powers that be at Tyne-Tees give it their blessing.

"We'll never run out of characters," he says. "Even those who always say that all the old characters have gone are turning into characters themselves and there is always something going on and all that wonderful countryside to show.

"The camera crew often ask me, if I wasn't doing this, what would I rather be doing and the answer is nothing. It's where I would want to be anyway on a day off."