Image caption Flintoff, Harris and McGuinness boosted the Top Gear audience from 2.2 million to 3.8 million

Paddy McGuinness has spotted someone rather important in the audience at the premiere of Top Gear's 28th series.

"Sir Tony! Get the Sambucas in son!" the presenter yells at the BBC's outgoing director-general Tony Hall at the show's Leicester Square launch.

Someone quietly telling him the DG is actually a Lord and not a Sir does little to dampen his spirits ("It's all the same anyway," he smiles the next day) and the overall mood of the night is resolutely upbeat.

And it's clear why. The show's new presenting trio of McGuinness, Andrew "Freddie" Flintoff and Chris Harris has been both a commercial and critical success.

"Top Gear is such a British institution," McGuinness tells BBC News. "The beauty of it is that it's an entertainment show which the whole family can watch - we're not just doing straight car reviews every week."

But the reliance on the entertainment element of the show's format is precisely why it faltered in 2015.

The departure of Jeremy Clarkson, Richard Hammond and James May left the series in a state of turbulence which lasted several years.

Image caption The series has been stuck in a rut in recent years, much like Paddy McGuiness's car

Ratings dwindled after the initial flurry of media interest, Chris Evans exited after just six episodes and Matt LeBlanc followed last February.

The subsequent summer, however, Top Gear's fortunes changed.

On their first series together, McGuinness, Flintoff and Harris boosted the previous average audience of 2.2 million per episode to 3.8 million. Their immediate popularity meant the show was finally able to put its years of difficulty behind it.

"Top Gear, when it went through that little problem phase, I don't think anyone ever wanted it to fail," McGuinness says.

"The thing about doing telly now, any telly, you've got all these social media platforms where people will instantly give you their opinion. Years ago, a show could bed in and have a bit of time to breathe and get a bit of chemistry going. We were lucky that we hit the ground running chemistry wise so I think that went in our favour."

When it came to recasting the show after LeBlanc's departure last year, putting a comedian, a cricketer and a car geek together was a risk.

"Thankfully, this reconditioned vehicle roared out of the garage," said Michael Hogan in The Telegraph when the new line-up debuted last June.

Image caption Top Gear's exec producer says the show is now 'less scripted' than it was in LeBlanc's era

"Top Gear might have miles on the clock, but this trio injected some va-va-voom. Their chemistry was immediate, their camaraderie warm."

The trio are now revving up for their second series together, which launches this Sunday and features a few stunts which are genuinely astonishing and borderline cinematic.

As revealed in the trailer, Flintoff is seen doing a bungee jump in Switzerland at one point.

Which doesn't sound particularly unusual, except that he has to do it in a car. Literally, a car plunging hundreds of feet through the air, with a world-famous cricketer in it, attached to a bungee.

Often, the stunts the presenters take part in are unknown to them in advance.

Golf balls and lube

"We like to be involved vaguely in the creative process so we know what's going on and we have some input," says Harris, "but actually, Top Gear is at its best when the producers spring something on you and we respond naturally to it.

"The more you know, the less realistic your reactions. So we're in that weird position of encouraging things to happen that we don't know about."

Other activities this series include racing round a track while being sprayed in the face with lube and driving through a golf range in open-top cars while being constantly pelted with golf balls.

And that's all just in the first episode.

The bungee jump stunt in the new episodes leads Flintoff to remark: "I'd like to see Jeremy Clarkson do this!"

Image copyright Amazon Studios Image caption Clarkson, Hammond and May acknowledged climate change on The Grand Tour recently

Since leaving Top Gear in 2015, Clarkson, Hammond and May have been kept busy presenting The Grand Tour on Amazon, a recent episode of which saw Clarkson explicitly acknowledging climate change for the first time.

Motoring programmes in general have been coming under more scrutiny in recent years as environmental campaigners lobby for change, something the new team are very aware of.

"Top Gear reflects the behaviour of the motorist in the UK," says Harris. "A good percentage of what we do is electric, and inevitably there's going to be more electrification in UK motoring, and we'll reflect that going forward. We're flying less, travelling less, doing more in the UK, so I think we're definitely acting responsibly."

'Far less scripted'

Harris's role as the show's resident car geek and reviewer is one part of the format which remains unchanged.

"We knew that Chris was definitely staying," explains showrunner Clare Pizey, who was tasked with recasting the series after LeBlanc and Rory Reid's departure.

"You have to have the foundation stones of what Top Gear's always been," adds executive producer Alex Renton, "and Chris has done an amazing job for us. I think we will always do car reviews in the show, we'll never lose that."

Image caption Chris Harris is the only presenter to have stayed on after the LeBlanc era

Harris has always enjoyed bringing the nerdy side of cars to Top Gear, but he particularly revels in doing so under this line-up.

"You can see how much happier and better Chris is working with these two, because they are just a trio," says Pizey.

McGuinness agrees: "If someone's watching a show, you can tell if that chemistry is real or not. And maybe that's why people bought into it, because they genuinely know we get on."

While the previous presenters LeBlanc and Evans were undoubtedly knowledgeable about cars, the new trio have recaptured the three-way chemistry the show was previously best-known for.

"It's far less scripted," notes executive producer Alex Renton. "I think it's well-known that in Matt [LeBlanc]'s day it was quite heavily scripted because of how we used to work, and now there's just the freedom, they know each other better and the chemistry grows more and more," he explains.

"A huge amount of the backroom stuff is the same, we've had the same crew for years, but there's something about when Chris, Paddy and Freddie are on set together, and it just goes off."

Pizey narrows down the show's recent success further, pinpointing: "I think it's [having] three Brits, I think it's Brits, post-Matt.

Image caption McGuinness posed for photos with fans during Top Gear's premiere on Monday

"I think because they all grew up knowing and loving Top Gear, they get the tone, it's instinctive."

As for how long he'd now like to stay in the job, McGuinness says: "If the show's a success, I'll carry on doing it as long as they want me to."

Harris similarly wants to stick around. "Unlike Fred and Paddy, I don't get many offers of work other than Top Gear, because I'm crap at everything else."

Having been through a few turbulent years, it's Pizey who perhaps sums it up the best when she says: "We don't want another change!

"I don't want to tempt fate, but surely, to goodness, we've earned the right to say it's fixed for a while. But don't tell them that when their contracts are up for renewal."

The new series of Top Gear begins on Sunday at 20:00 GMT on BBC Two.