In one corner of a cavernous studio in Elstree, the unmistakeable silhouette of Marouane Fellaini is bouncing high on a trampoline under a rain machine in scenes unlikely to do much for David Moyes's blood pressure. In another, Liverpool's Daniel Sturridge is being filmed on a giant hamster wheel.

BT Sport's expensively acquired big name hires from the BBC, Jake Humphrey and Clare Balding, weave in and out of the action as gaggles of clipboard-wielding assistants buzz around shouting into walkie-talkies about pressing crises such as Thomas Vermaelen having the wrong-sized shorts.

Somewhere amid the mixture of tedium and mayhem of a big budget advertising shoot, those behind BT Sport's multimillion-pound marketing campaign to announce itself to a sporting public used to Sky Sports are nervously awaiting the moment when they will unveil their proposition to the world.

The public face of that assault will be Humphrey, who fronted the BBC's Formula One coverage before he jumped ship for BT. From a makeshift dressing room, he says the mixture of excitement and trepidation reminds him of when he was tasked with making the leap from children's television to a sport with one of the most committed and demanding fanbases.

"They announced it at 10am on a Thursday morning and my wife rang in floods of tears at 10.30am saying she'd just been on the internet and everyone was saying I was going to be shit," he recalls.

"I asked where she'd read it and it was on the BBC Sport website. There were already 250 or 300 messages under the headline 'Sack Jake Humphrey now'."

With the BBC having given up the live rights to half of their grands prix under a renegotiation of their contract and Gary Lineker seemingly immovable as the main anchor of the BBC's football and major events coverage, Humphrey says that as soon as he knew BT were prepared to invest for the long haul he was convinced of their ambition.

"I was trying to build a good career at the BBC, so it was a big move to walk away. What compelled me to do it was the ambition. I wanted to know if they just wanted to be in it for three years to sell a few internet connections," he says.

"They told me their plans for the studio on the Olympic Park and it got me thinking that just as the BBC were shutting down TV Centre, which I've always called home, there's BT building something that is going to be a third of the size of TV Centre. They are showing incredible ambition. They're talking 10 years plus, they're here for the long haul. I don't think you spend £738m on football rights to disappear after three years. You do it as part of a long-term plan."

BT Sport's marketing manager, Alfredo Garicoche, is more effusive still: "We're not thinking for the next two or three years, we're thinking for the next 20 or 30 years and even longer. We're here to play the game. We have the financial backing to play the game and play it well."

BT executives insist their big gamble on sports rights as a driver of broadband subscriptions is a long-term bet, having already splashed out £1bn on rights and taken a 10-year lease on new studio at the Olympic Park in Stratford.

They also insist there is a gap in the market for a different kind of presentation, subtly different from Sky's high-stakes, hi-octane world of Super Sundays and endless hype.

"We've talked internally about it being sport with a smile," says Humphrey. "You want people to turn on and not be sure whether they're watching BT or the BBC. Really good production values, really nice, accessible, open coverage.

"Sky have done a brilliant job and we'll have a big task to match up to the quality of their coverage but I do think there is room for improvement and to add my own stamp on it. I want to make it a warmer, friendlier, a more personal experience. Everyone knows a lot about the Premier League but we can open it up even more and get even closer to the names and the faces," adds the 34-year-old, who is a lifelong Norwich fan.

To that end, BT has signed up a series of "ambassadors" including Robin van Persie, Gareth Bale and Alex Oxlade-Chamberlain and is making noises about a renewed tilt at persuading Premier League clubs to be more open about where they allow cameras to go on matchdays and during the week.

Most of BT's live matches will be in the Saturday lunchtime slot and Humphrey says that once viewers have tuned in, part of the task will be to keep them for the whole day. Like an updated version of the BBC institution Grandstand, he envisages presenting from the studio or from big grounds around the country for the entire afternoon, passing from one sport to another and bringing the "crackle of live sport" to the nation.

"You'll switch on first thing in the morning and won't want to switch off until last thing at night. That's the plan. It's important we give equal standing to everything. If you like rugby, the only place you'll be able to see it is on BT. We've got the tennis. It's important all the other sport is on a level playing field."

Taking a break from perusing storyboards that variously show Fellaini challenging the Saracens No8 Ernst Joubert as he leaps for a lineout and Humphrey avoiding tennis balls fired at him by Heather Watson, Garicoche adds: "Our style is going to be different. We like to say it's sport with colour, sport with fun. More engaging and approachable maybe. We like the word inclusive as well."

Whether there is room in the market for a cheaper, more family orientated alternative to Sky is the £1bn question for BT executives. Sky, not used to losing and having seen off pretenders including Setanta and ESPN, is already fighting back by tying up all its most important rights for as long as possible and training its guns on its new rival.

The other big names who will appear alongside Humphrey are expected to be unveiled on Thursday, but the presenter believes that BT owes Gary Neville, Sky's star signing who has breathed new life into its coverage, a debt of thanks.

"What is brilliant is that Gary stepping straight out of the most famous dressing room in the country and on to TV opens us up to pretty much every player who is looking to retire. That is brilliant for the fans at home," says Humphrey. "For a long time it felt like pretty much every pundit managed or played 10 years ago. There was a real generation gap. Now, the feeling is that we need someone who has just stepped out of a big dressing room."

Sky revolutionised sports broadcasting when Rupert Murdoch bet the farm on Premier League rights 22 years ago, but Humphrey believes there are things BT can do to subtly move it forward again. The cavernous studio will play host to a half-sized football pitch, where pundits will demonstrate what players did or didn't do correctly and there are other technological innovations planned that marry broadband interactivity with live coverage.

"With me being in my early 30s I'm not scared of technology, I've grown up with it – playing computer games and doing all that stuff. I want to delve into that. But at the same time, we don't want to lose the human element," says Humphrey.

The biggest winners in the battle between BT and Sky are likely to be the Premier League, which has banked a total of £5.5bn for its TV rights over the next three years. Its executives are rubbing their hands together at the prospect of an ongoing, bitter battle for rights between two of the biggest media companies in Britain.

"I think BT was established in the late 1800s. We aren't going anywhere. We understand that content is key and sport is key for that," says Garicoche. "We want to go after the fans, after the people who can't pay or can only pay less. In a way, we want to democratise sport."