Sunseeker numbers oligarchs, royalty and sports stars among its customers. As the company celebrates a £320million takeover and the launch of the world’s largest superyacht, we were granted exclusive behind-the-scenes access.

We have split the atom, put men on the moon, brought down the Berlin Wall and raised the Iron Curtain. But the inner workings of Sunseeker have remained a mystery - until now. The Dorset-based luxury boat behemoth prides itself on keeping one bow-wave ahead of the competition and guards its multi-million-pound secrets as hawkishly as NASA. So, who could resist an exclusive sneak-and-peek behind the scenes of this shipbuilding giant that has, for more than half a century, built some of the world’s most lavish super yachts for the rich and famous?

As Sunseeker celebrates its £320million takeover, we were granted unique access to the rarified world of Simon Cowell, Eddie Jordan and the King of Belgium – not to mention James Bond - to witness what really goes on behind Poole’s famous blue gates.

The low-key entrance, albeit flanked by two top-of-the-range Porsches, proffers little clue as to what lies within. But when Colin Rowles, a senior broker who has worked here since joining as a 16-year-old apprentice 35 years ago, hands me a price list, it becomes immediately clear that only the very, very rich need apply.

I could barely afford the four-foot scale model in the lobby, let alone the full-size fibreglass hulks that lurk within. Models range from £450,000 – for Sunseeker’s entry-level 40-footer – to £22million for their brand new, industry-defining 155ft superyacht, already snapped up by F1 billionaire Eddie Jordan, a close friend of Robert Braithwaite, the surprisingly down-to-earth Yorkshireman who founded the company 53 years ago.

Under his leadership, the company that started out with seven people now employs 2,400 in Poole alone, the largest manufacturing employer in the South West, turning out 200 boats a year, with an annual turnover of £320 million. Not bad for a business that, just five years ago, was £35,000 from going under.

Robert oversaw June’s buy-out – by Chinese property developer Dalian Wanda – but, at 70, he is still very much hands on, at his desk four days a week.

We catch up with him over lunch at Hotel du Vin. Twinkly and dapper in open-neck shirt and deck shoes, he has the gleam of a man whose work is his passion.

“Fibreglass is my mistress, always has been,” he says jovially. “And we’ve come a long way together. I left school when I was 14, with no qualifications.

“My parents ran a draper’s shop in Otley but we used to go on holiday to the Lake District and take our small boat. The water became my life. I designed my first boat when I was 17 and never looked back.”

His yachts have starred in no fewer than four James Bond films. Robert even had a cameo in 2008’s Quantum of Solace, appearing on screen alongside 007 star Daniel Craig in a vintage Sunseeker.

But his new 155 – so large that engineers had to build a special tent at the shipyard just to house it - is perhaps Robert’s proudest moment.

The yacht, the first of its kind, will finally be complete in March after two years of construction carried out by a dedicated 76-man team.

Robert says: “The 155 is my baby. There’s nothing else like it. Because of its unique infused build, it’s 200 tonnes lighter than any of its competitors.

“Eddie’s been a good customer – he’s bought 17 of our boats now – and he’s become a good friend. He’s going to love this boat. Who wouldn’t?”

Not the boss, for one. Robert doesn’t own one of his own boats; he prefers his 24-foot shrimper and rib, moored up on the River Yealm in Devon.

“I had a Sunseeker when the children were small but, to be honest, they’re a bit too flash for me. My two boats are all I need.”

Robert prides himself on a family approach. Many of his staff have worked here for years, but they always refer to him as The Boss, regarding him – and his boats - with a reverent awe.

As Colin – whose team sells up to 20 new yachts a year - says: “Sunseeker is just a fabulous product.” So too, of course, is their customer list, from Hollywood stars to oligarchs.

Colin – just back from Montenegro after personally handing over the keys to yet another new owner – adds: “Our clients are power players. They want and expect the very best. Some we can mention, others we can’t. Chris Evans is a good customer, so is John Caudwell. The King of Jordan’s bought a few. Simon Cowell’s a fan too – but he only charters, he doesn’t want to buy.”

Nearby Sandbanks boasts some of the most expensive real estate – and richest homeowners – in the world and Colin is not above touting for business. His Cheshire-based colleague Jonathan Kingsley, 46, agrees: “You can sit waiting for the money or you can go out and chase it.”

Colin recently tapped up famous local Harry Redknapp, manager of Queen’s Park Rangers. He laughs: “He might live on the water’s edge but he didn’t want a boat. It turns out he suffers from chronic sea sickness.”

But this is undeniably big business: from the 125,000-square-foot Technology Centre in Tower Park - where interiors and gadgetry are designed, built and tested - to the nine-acre shipyard on the quay where the fibreglass boats are put together.

Staff work from 8am to 4.15pm, five days a week, but their shifts have to be strictly controlled. “If we let them out all at once, we’d bring Poole to a standstill,” says Colin.

Unlike their competitors, Sunseeker manufactures 70 per cent of its own components – a business with a yearly £60million turnover in its own right - on site: the doors, the equipment, the interiors. The industry average is just 30 per cent. Every year, Sunseeker handles and fits 880,000 miles of electrical cable, enough to travel to the moon and back.

There are three computerised cutting machines used to fashion the marine ply – the main material - but almost everything is finished by hand. There are no robots here.

Everything has to be just-so - or it goes in the bin. According to a stern poster on the factory wall, £1million of raw materials are “unnecessarily wasted” every year. The attention to detail is painstaking.

Before any new Sunseeker goes into production, the interior is built to scale in plywood to test for any issues, as Colin explains: “We need to make sure everything works. Sometimes, very rarely, the drawings don’t match reality – a corridor’s too narrow or a door can’t open fully.”

What becomes of these lovingly-constructed facsimiles?

“They’re broken down and turned into sawdust,” Colin tells me, matter-of-factly.

This is the very definition of bespoke. What the customer wants, he gets: from Bang & Olufsen sound systems to £500,000 gyms and secret gun lockers, even £300,000 “touchpads” to allow transit by helicopter.

Clients – judging from the impossibly glossy brochure, studded with pictures of sinewy men of a certain age behind the wheel and young bikini-clad beauties sprawled across the sun decks – are generally male.

Jonathan adds: “I’m sure we do have some female customers but I can’t think of any off-hand. Men like to drive, women like to sunbathe. Generally.”

We wander round one of these immaculate model interiors - a mock-up of a new, £8million, 101ft Sport Yacht built for a long-standing customer that has taken three months to perfect.

The master cabin comes complete with a six-foot LED image of a black skull above the bed. Money is, of course, no guarantor of good taste.

This may be the nerve centre but the power house behind Sunseeker’s success is the shipyard, made of up four separate “sheds” dedicated to the 23-model range. Here, the fibreglass hulls are moulded, fitted out and tested before taking to the water.

Shed One turns out the 84ft, 88ft and 28m yachts – three at a time. Each takes five months and up to 80 men – the workers in the shipyards are all male - to build, in five four-week stages.

But the new 155 is the prize – a good 25ft longer than anything Sunseeker has built before.

Named The Snapper – like all of Eddie Jordan’s Sunseekers – this monster of a boat will ultimately be moored in Cannes.

There are three decks, a beach bar and berths for 10 guests and 12 crew. The 60,000-litre fuel tank – enough to power across the Atlantic – will cost an astonishing £60,000 to fill.

But billionaires are rare beasts. Despite the fact that this boat would happily tower over Buckingham Palace, Eddie’s surprisingly austere master cabin barely contains its essentials – a 5ft double bed, a bath (sadly without gold taps) and a running machine.

Colin says: “He just wants what he needs in his cabin. He’s only ever going to be there to sleep.”

Project manager Peter Stembridge, 53 – a trained surveyor and naval architect who worked on the complex design – adds: “This is a real game-changer that will take Sunseeker into another league. The 155 will be the only boat of its kind in the world – there is nothing else this powerful and grand but this light.”

But no trip to Sunseeker would be complete without a trip out on the water. Production manager Ashley Cooper, 43, shows us aboard Emocion, a just-finished, £12million 115ft Sport Yacht.

As he eases out the throttle and motors across Poole Harbour, you would barely know that you were on the water.

The interior resembles a gentlemen’s club in Mayfair – wall-to-wall satin walnut and Miele appliances, even in the plush staff quarters.

But Ashley’s last build, for a Mexican oil tycoon, was arguably even swisher. “He just loved beautiful things,” says Ashley. “Even his knives and forks on board were all solid silver – they cost £475 each.”

As we unhappily reclaimed dry land, I have seldom felt so exhilarated – or so skint. Sunseeker may be a foreign country, but it’s a wondrous one.

Discover more at sunseeker.com