In the summer of 2018, Englishman Paul Mitchell was at his home just outside of London, planning a round-the-world trip to celebrate his upcoming 40th birthday.

He started surfing travel websites leisurely, but ended up on Google Maps frantically trying to locate a particular carpark in Singapore.

Something had caught his eye on a travel blog. Among parked cars in an industrial estate, he spotted a partially concealed nose of a dark-coloured sedan, which he somehow deduced was a Lotus Carlton - an ultra-rare super-saloon from the 1990s.

It also happened to be a car he has been obsessed with since childhood.

The Lotus Carlton was a mutant version of the Vauxhall Carlton sedan of the era. Its engine and chassis were heavily tweaked by British automotive company Lotus, which hand-built the car at its factory.

With a 3.6-litre twin-turbocharged six-cylinder engine that delivered 377bhp, its output dwarfed that of even the BMW M5 of that era, which put out 315bhp.

It propelled the Carlton to a top speed of 285kmh, making it the world's fastest production saloon when it was unveiled in 1990.

Its output and performance were so jaw-dropping, it sparked a parliamentary debate in Britain on whether the car should be banned - something which only fuelled its notoriety. Fewer than 1,000 units were built and even fewer survive, so it is now highly collectable.

Anyway, back to Mr Mitchell. Even as car fanatics go, the 41-year-old property investor is pretty extreme.

Over the last 15 years or so, he has amassed about 50 cars, mainly performance models from his growing-up years. The stable includes a Renault Clio Williams, Ford Sierra Sapphire Cosworth, Audi Quattro and Chevrolet Corvette, as well as esoteric cars like the Mercedes 500E, BMW 840ci, Renault Clio V6 and Isuzu Piazza Turbo.

He also has no fewer than four BMW E34 M5s, including an extremely rare six-speed Touring.

One car the bachelor would really like is a Ferrari F40, which he regards as "the ultimate supercar". But until then, he makes do with an F355 Spider, which takes centre stage in, of all places, his kitchen.

He says: "They're all cars which have meant something to me through the years."

For instance, his affinity for BMW M cars stemmed from the rasp of their engines which enthralled him as a child. The two-tone Isuzu Piazza made him realise that cars need not come in a single colour scheme.

Despite his collection, he is most passionate about the Lotus Carlton.

The seed of his fixation was planted when he visited the Birmingham Motorshow with his father in 1990. There, he was smitten by the sight of the brooding, brutish-looking hulk of a car.

"Two British companies run by petrolheads - Vauxhall and Lotus - teamed up to make something outlandish based on a normal car and this was the result," he recalls. "That was where it all started for me."

By the time he chanced upon the photo of what he calls "the Singapore car" in August 2018, he already had a Lotus Carlton, which he bought in 2001. In fact, it was the first car he bought after graduation.

Still, he could not resist hunting the Singapore car down.

"The Lotus Carlton, for me, has always been top of the tree. So, if the right one comes along again at the right price, I would buy it."

He spent a few evenings on a virtual tour of Singapore on Google Streetview to try and pinpoint the location using background clues from the picture, eventually succeeding in identifying it as an industrial estate in the east.

Over the next two months, through countless letters and e-mails to businesses operating in that vicinity as well as other contacts, he tracked down the car's custodian. It took another three months for both parties to come to a sales agreement.

He declines to say how much he paid, but a similar model was sold at an auction in Britain for £45,000 (S$78,000) earlier this year.

During Chinese New Year last year, he flew to Singapore and finally set eyes on the car.

It was a sorry sight, having been left in the open for the best part of a decade. The exposure had ruined its paintwork, the tyres were in a bad state and the cabin trim had disintegrated from the heat. But, thankfully, the body was almost rust-free.

It turned out that the car's custodian was not the original owner.

The Carlton was imported in September 1991 by a collector, but never registered. Some years later, he disposed of the car, which is how it ended up abandoned in the industrial carpark.

When Mr Mitchell took over the car, it had just over 3,200km on the clock, meaning it probably had not been driven since it landed in Singapore. Even the fuel tank had been dismantled and stored in the boot.

Mr Mitchell left Singapore after arranging to have the car shipped to Britain. In the weeks before the car arrived, he converted his garage at home into a workshop, installing a hydraulic ramp, a hoist, a workbench and other equipment.

The car landed rather timely at Southampton Port - the day after Mr Mitchell's 40th birthday.

Since then, he has refreshed the engine and completed a great deal of other mechanical work himself.

On April 15, when the reassembled engine started after laying dormant for three decades, it was an emotional moment.

The car's leather upholstery and cabin trim was restored or replaced.

But there is more work to be done. Up next will be a body restoration and a respray in the original Imperial Green - a dark metallic green which incidentally was the only colour the Lotus Carlton was ever produced in.

Since acquiring the Singapore car, Mr Mitchell has bought another Lotus - an accident-damaged Opel Lotus Omega (a Lotus Carlton rebadged for the European market) from France - which he will restore once he is done with the Singapore one.

While most of the cars in his stable are stored under wraps in a barn about 40 minutes' drive from his house, the three Lotus rides are kept in his home garage.

And of the three, the Singapore car is the most special to him - partly because of how he found it, but also because it seems like he was destined to own it.

"It was just perfect, the fact that it had been hidden out of the country for 28 years and I was able to find it, bring it back and restore it. It just doesn't get any better," he says.

He estimates that by the time the restoration is completed, he would have forked out about £25,000.

Not that it matters. It is, after all, a lifelong investment for him. "This car will reside with me for the rest of my life. I won't ever sell it," he says.