Tuning into Highland Radio as you cross into north Donegal, it could at first be mistaken for a BBC station. A presenter with a north of England accent is interviewing another man with an English accent about car testing. By the time you realise that they are talking about the introduction of vehicle safety checks in the Republic, a listener has rung in to question why the company running the testing procedure is "not Irish".

Of course nobody questions why the interviewer is "not Irish". The fact that Sean Doherty speaks with a strong north of England accent hasn't prevented him from building up a listenership unequalled in market share by any other programme on local radio in the State. His is the flagship slow on Highland Radio.

"From day one I was lucky that people took to me, and even though I've an English accent, having Donegal roots and having a name like Sean Doherty has helped a lot." He says people didn't need to ask him about his family connections, they already knew them.

Broadcasting from a hilltop high over Letterkenny, Highland Radio can rightly claim to be king of the local independent stations after last week's Joint National Listenership Research (JNLR) figures. It was found to have a market share of 74 per cent, an impressive 18 percentage points ahead of the next best performer, Mid West Radio in Co Mayo. In the "listened to yesterday" scores, Highland was also way ahead at 75 per cent. RTE radio, it would appear, is fast becoming a distant memory for most Donegal residents.

Highland Radio has worked hard to be popular, and profitable - JNLR figures like that will impress any advertiser - but when it comes to the crunch, station manger Charlie Collins says commercial considerations come before any expectations held by people in the community.

"People considering us a community station is still very much a factor, but I would be at pains to point out at every opportunity that this is a commercial radio station. It is a business, it's about making a profit to pay the wages and to keep the thing afloat.

"However there is a strong community element to it as well that we can't afford to ignore, because it makes us different from other people, and we've got to try to find a balance somewhere between the commercial and the community that will make the thing work." He gives the example of people who ring in to say they want some event "mentioned" but don't expect to have to pay, even though they have paid for an advert in the local papers.

A factor in Highland's success has to be its location, and the fact that socially and politically Donegal has occupied a space somewhere between the Republic and the North. People often feel ignored by the Dublin media and then happily ignore it back. Donegal, says Collins, has been in "splendid isolation" and people in the county are also naturally loyal to their own. Highland Radio is perceived as their own, and when they want to hear about local issues it is the place they turn to.

Having worked on pirate radio, as have most of Highland's presenters, Collins says the success of the pirates showed that RTE was losing the battle even before independent stations went on air.

"It seems to me that RTE have almost thrown their hat at it. I'm interested in comments when these surveys come out about how pleased they are with the Dublin market, but they shouldn't forget that they are a national broadcaster."

Highland has a consistently higher listenership throughout the day than other local stations, although its formula is not hugely different. Its strategy of getting listeners early in the day and keeping them for as long as possible is working. So 65-year-old Packie Bradley, who didn't let a heart bypass operation some years ago keep him off the airwaves, achieves afternoon audience figures twice as high as other local stations with his programme of Irish country music.

The Sean Doherty programme from 10 a.m. to 1 p.m. is seen as a key to the station's success. Focusing on current affairs, it aims for as much audience participation as possible and the show is regarded as a success primarily when the phones are hopping.

Doherty, with a typically north of England down-to-earth approach, appeals to listeners, and sounds much older on air than his 35 years. In person, he sports a wet-look hairstyle spiked at the front and wears dance-club-style clothes, despite the fact that most listeners think he's "aged 50, balding and wearing a suit".

Trying to explain the success of his show, he puts it down to experience at this stage, and the fact that he can "talk to anyone". People tell him this is what they like about him.

Hard work is also likely to be a factor however. Most of the main presenters have other jobs at the station - one is a sales rep in the Letterkenny area, another works on the technical side of things. Doherty is promotions manager, organising trips in Ireland and abroad and regular concerts. A forthcoming 1,000-ticket concert sold out within days. The net effect is that the station makes more money, relationships are forged with listeners and Doherty's profile is raised.

In total the station, which is owned by six local people, has 22 full-time staff and 25 more who work part-time. Its franchise area is north Donegal, from a line just north of Donegal town, with a population of 77,000 over 15 years of age. Parts of south Donegal are served by North West Radio in Sligo.

In news coverage, emphasis is very much on local stories, but "the North" is regarded as a local story, and dominates the news at times. Council meetings in Derry and Strabane are covered just as they are in Letterkenny, as are GAA matches in Derry and Tyrone. Northern politicians, of all persuasions from the DUP to Sinn Fein, feature regularly. Again this is a policy that is both popular and profitable. While the majority of the Donegal population would hardly want a "partitionist" approach, listeners in Derry and Tyrone mean more revenue. Of local advertising, between 25 and 30 per cent comes from across the Border.

For the future Charlie Collins knows things can't get much better. He says if he could keep the figures as they are for the next five years, he would be more than happy. "Realistically it is difficult to see us getting past 75 per cent, but we will keep trying."