Can Sky Sports News keep punching above its weight?

Kay Burley might wring her hands with jealousy. Adam Boulton might turn puce with anger. But there's a commercially run rolling-news channel that's now trouncing Sky News in the ratings on a regular basis.

And Kay and Adam don't have far to look if they want to know its secrets: Sky Sports News (SSN), based on the same sprawling site at Isleworth, near London's Heathrow Airport, is the satellite broadcaster's best performing news channel. And that's not even counting the viewers who watch in the pub. A service that began life as an hourly update on Sky News has, for many sports addicts, become their default channel.

Rather belatedly, the network has been identified as a key asset by BSkyB, which at the start of the football season is preparing for a bruising commercial battle with Virgin Media, BT and Top Up TV. Rival broadcasters have been granted rights by the media regulator Ofcom to offer the Sky Sports 1 and Sky Sports 2 channels at a knockdown price. As part of Sky's response, SSN – once given away for nothing on Freeview as little more than a marketing tool – is being put behind a paywall, in line with a broader strategy of charging for content across Rupert Murdoch's global media empire.

The executive editor of Sky Sports News, Andy Cairns, is not one of Britain's most high-profile journalists. Yet he oversees a national newsroom of 140 staff tasked with breaking stories around the clock. Don't turn on SSN and expect to see the sort of famous ex-players who host Match of the Day or analyse Test matches. "We go for journalists," says Cairns. "We are a news channel."

In fact, he's such a stickler for reporting standards that he's in talks with the National Council for the Training of Journalists to refine courses for those who aspire to careers in sports news. It's not greater expertise in technical gadgetry that he's demanding. "Accuracy. You can't beat accuracy," he says, complaining of the decline in training opportunities on regional newspapers. "With all the difficult names in the Sri Lankan cricket team, and the Slovakians now playing in the [football] Championship, you have got to get them right."

Spelling mistakes look so much worse when revolving on the news ticker at the bottom of the TV screen. Mike Wedderburn, who begins presenting the channel's Good Morning Sports Fans segment at 6am, makes sure he's at work two hours earlier to read up on developing stories and minimise the risk of being stumped on air by the name of one of Muttiah Muralitharan's Sri Lankan teammates. And Wedderburn was once a bowler on Hampshire's books. "There's lots of planning from the presenters before they go on," says Cairns. "It's not just reading off the autocue – they have to do their research."

Soon after I arrive, the ticker has "turned yellow", indicating a breaking story. Andrew Flintoff has failed to recover fully from knee surgery and will not play cricket again this season. In the studio, Rob Wotton, sat alongside Hayley McQueen (daughter of former Scotland and Manchester United defender Gordon), announces the news to viewers. In the adjoining gallery, producer Vik Varange is barking out orders, slotting this breaking story in alongside the developing tale of the attempted purchase of Liverpool FC by a Chinese consortium.

Cairns has seen at close hand the transformation of the sports media in the past 25 years. As a sports producer at BBC News back in 1987, he remembers trying to persuade his bosses of the importance of audio and video footage of the England cricket captain Mike Gatting in a face-to-face confrontation with the Pakistani umpire Shakoor Rana at a Test match in Faislabad.

"We had that as an exclusive, and we really struggled to get that on the Six O'Clock News that night," he says, still incredulous 23 years later. The incident caused uproar and led to neutral umpires being introduced for Test matches.

Sport was such a poor relation in terms of broadcast news that when, in the Nineties, Sky News introduced a designated sports segment at 20 minutes past the hour, doubts were expressed as to whether sufficient material could be found to fill it. "People said, 'How's that going to survive?'" recalls Cairns. SSN launched as a stand-alone channel in 1998, but with regular American sports content from Fox plus other shows intended to offset a perceived shortfall in news.

Today, the station stands accused of overdoing its news coverage. Cairns has heard claims that the ticker was once turned yellow to report a star's broken toenail – an apocryphal story, he says. Nonetheless, Sky Sports News is set to expand even further. A fleet of three live trucks sent out each day is being expanded to six. If a sporting envelope is being opened, SSN will be there to film it.

On the day I visit, there is a live truck at Headingley, for Yorkshire's cricket match with Nottinghamshire. In a live link, reporter Mark Dexter breathlessly relays that the home side, having lost a wicket, have "scored their first run". A sparse crowd is looking on. "That's an important game," Cairns protests. "There's been a wicket in the first over; it's like a goal in the first minute."

Ahead of the upcoming battle with rival broadcasters, Sky Sports News is undergoing a major on-screen redesign. The side panel which currently shows random league tables and fixture lists will soon display graphics that relate directly to the story in the main part of the screen. SSN's introduction of high definition on 23 August will increase the visibility of additional footage shown in a small box in a corner of the screen. Cairns also plans specialist podcasts on Rugby Union and golf, as part of the channel's attempts to broaden its coverage of sports other than football.

It recently sent reporting teams to The Open, Wimbledon and the Cheltenham Festival. The newsroom's production teams – each 12-strong and headed by a producer and a chief sub – are encouraged to develop stories, hour by hour. "We've got to find a new lead, new information, new treatments," says the executive editor.

With so much space to fill, the channel is vulnerable to those who might try to exploit it to further an agenda. Cairns admits that football agents will attempt to feed the channel stories of transfer rumours that can add to the value of their clients. The rumours are bound to increase later this month with the approach of football's transfer "Deadline Day", one of the highlights of SSN's year. "You should do the proper journalism and put the checks in," Cairns says, adding that what the channel does not broadcast is as important as what it does. Presumably he does not wish to attract the nickname that BBC journalists like to attach to the fast-moving Sky News: "Never wrong for long."

As newspapers strengthen their online output (and new sports websites emerge), so SSN faces greater competition in trying to break news. Cairns says his channel enjoys a warmer relationship with sports stars than do some sections of the press. "We don't go out to shaft anybody, we don't call for anyone to be sacked," he points out.

That rapport is strengthened by Soccer Saturday, the popular results programme hosted by Jeff Stelling and featuring the punditry of ex-professionals such as Paul Merson and Charlie Nicholas. That show is being taken off Sky Sports 1 this season, in a strategic move to further enhance the value of Sky Sports News.

If anything can dampen the hype that surrounds a new football season, then surely England's dismal display in South Africa is it. Yet Cairns disagrees. "England is just for the big tournaments," he says. "People support their club every week." Or in the case of Sky Sports News addicts, every day, every hour, every minute.