“No, I’ve never had nerves in my life!” a relaxed Gary Lineker exclaims from his seat when asked if he ever gets butterflies in his stomach before going on air.

It is thirty minutes before he addresses the nation’s football viewing public for Manchester City’s Champions League clash with Monaco and there is a surprisingly convivial atmosphere inside the BT Sport studio.

Alongside Lineker are pundits and former players Rio Ferdinand, Steven Gerrard and Richard Dunne who share the odd joke and give the claustrophobic studio the feeling of a changing room - except in the place of muddy boots, bits of tape and isotonic drinks are a tissue with smudges of make-up, tins of biscuits and half drunk cups of coffee.

Aside from those star names cramped into this 15 feet square box are two cameramen, a sound technician and an operations manager whispering instructions into a walkie-talkie. They are among the 100 or so unseen BT Sport employees at the Etihad making sure their broadcast runs smoothly.

For all the sense of relaxation in the studio-cum-dressing room, there is an undeniable air of attention to detail. Lineker has been running through his autocue script for the night, something he writes himself, while shouting out amendments where he finds a mistake or a turn of phrase he dislikes.

“Welcome to the Etihad…” his voice trails off. “We can’t call it that can we?” he muses while listening to a producer in his earpiece. “The Uefa thing,” Lineker adds, referring to the footballing body’s strict rules on sponsorship and naming rights.

“People on Twitter will go mad. I did it the other week and.. meh, meh, meh.” He gestures with his hands mimicking the mob on social media who will jump on the slightest of mistakes.

Eventually, coming to some agreement on the exact wording, Lineker continues, shouting out his script much louder than you appreciate when watching on television at home.

Just as he wraps up the rehearsal, the team sheets are released and the studio buzzes into action once again.

The exclusion of Valere Germain for the visitors is the only surprise. The voice of Matt Smith crackles from a nearby monitor: “Where’s Germain? Where’s Germain?”

“Yer man, yer man,” Lineker responds with glee, slapping his thigh while turning to Dunne. “I didn’t realise there was an Irishman playing for Monaco!” The panel chuckle in unison while trying to decipher the formation City will line up in.

There's no doubt that BT Sport see the Champions League as their jewel in the crown

Dressing room banter finished, the team then put together the final touches to what has been several hours of preparation for 45 minutes of build-up chat.

Their work started for the day in a Hollywood-style portable trailer in the sprawling car park outside the Etihad. The broadcast team - which includes commentators Darren Fletcher and Steve McManaman - are given a package of information on both sides by BT researchers.

Smith, who will later be grilling managers Pep Guardiola and Leonardo Jardim in the tunnel minutes after full-time, pops out into the Manchester drizzle for a quick chat.

“I’d do this on my day off,” he says joyfully before reeling off the names of the young Monaco players - Kylian Mbappe, Bernardo Silva et al - he is looking forward to seeing in the flesh.

But having a day off looks unlikely for Smith and his colleagues now that their employer has paid £1.2bn for exclusive Champions League rights until the end of the 2020-21 season.

While BT hosts a large chunk of Premier League action, there is no doubting that European football’s elite club competition is its biggest draw.

The Champions League TV rights in the UK went to BT Sport for £1.2bn

“Look, the ideal is to be involved in the Champions League in one way or other,” explains Simon Green, the bespectacled head of BT Sport, speaking at Manchester City’s football academy earlier in the day. "We're in the long-term business of bidding for rights now and part of that is winning them and part of it is losing out.”

There had been some suggestions that Uefa would look to split the rights between BT and a terrestrial broadcaster - ITV was among the favourites - in order to expand the audience for Champions League games in the UK.

"It's up to Uefa,” Green adds. “The money is a large part of it, but not the be all and end all for them. They may choose to take a chunk away and offer it to another broadcaster."

Some of BT’s viewing figures are thought to have worried Uefa, but £394m per year - and the promise to show highlights on social media - was enough to persuade them otherwise in the deal announced this week.

“BT Sport has proved to be an innovative broadcast partner, pushing the boundaries and covering the Uefa Champions League and Uefa Europa League in new ways,” Uefa’s marketing director Guy Laurent Epstein said as the deal was announced on Monday.

Gary Lineker writes and practices his own script for hours before going live

Green, a Watford fan, is at pains to point out that football is just a tiny part of the wider business, highlighting the billions of pounds lost after an accounting scandal in its Italian subsidiary which saw 20 per cent wiped off its share price in January.

But with its television subscriptions playing a vital role in attracting customers to its larger telephone and broadband services, was there really any choice but to go all out and secure exclusive rights on the Champions League? For all that Green talks it down beforehand, the fact his company paid a 32 per cent increase on the current three-year deal, and that its share price was immediately boosted by the news of the deal, tells its own story.

Despite those disappointing audience figures, Green is bullish about BT Sport’s standing in the market, even suggesting the BBC has started to ape his channel’s more relaxed style.

That informality - open-necked shirts, three-man commentary teams, the organised chaos that is Saturday afternoon’s BT Sport Score - is all part of a commitment to being “authentic”: a buzzword dropped into several conversations by BT employees.

Not that it always wins them fans. The broadcaster came under fire last season when Ferdinand said he wanted Manchester City to lose in the Champions League. But Green says that is all a part of its allure.

"When Rio Ferdinand turns up to the studio, we want him to be Rio Ferdinand,” Green adds. “Sometimes it gets us in trouble but having that is important to us.”

The studio resembles something of a dressing room filled with ex-professional footballers

Back inside the studio and Lineker is checking his phone, looking at the latest updates on Twitter - his favoured means of communication with the outside world. Does he check-in during the ad breaks? “No!” he insists, alluding to that aforementioned mob pointing out the slightest mistakes. “Never, ever the check the notifications!”

Putting down his phone, Lineker later concedes there is “a bit of adrenalin, for sure,” when pushed on those pre-match nerves, before concluding with a grin: “But it’s just talking football, isn't it?”