The "game-changing" computer first went on sale on 24 January 1984, two days after being introduced to the world in a big-budget Super Bowl advert, by renowned British director Sir Ridley Scott.

The advert, referencing George Orwell's dystopian novel 1984, was itself considered a watershed moment in advertising - later being described as "more successful than the Mac itself" by Apple's then marketing guru Regis McKenna.

Starring the British athlete Anya Major breaking a screen showing the book's chief antagonist Big Brother, the advert ended with the tagline: "On 24 January, Apple will introduce Macintosh. And you'll see why 1984 won't be like '1984'."

Ron Gutman, an inventor, healthcare and technology entrepreneur and Stanford University adjunct professor, said the "legendary" video correctly foreshadowed the change the new machine was about to bring.

"[It was] a symbol of overturning the era of Big Brother PC makers that was more functional and business management-focused into a consumer-facing, easy to use and beautifully designed Macintosh," he told Sky News.

"Apple highlighted the geeks behind the scenes - engineers and designers - making them the rock stars that created a new paradigm of relationship-computing and delightful user interaction."

While the big-budget advert to promote the computer was deemed a massive success, the computer itself would prove groundbreaking in its own right.

Its most significant development was its move away from the traditional command-line interface of blocky text in favour of a graphic interface of logos and icons we still see today.

Dr Robert Jones, a tech expert and data analyst for tech firm Hackr, told Sky News: "Before the Mac, most personal computers still required typing in codes and commands just to get anything done.

"Only real tech wizards could figure it out. But the Mac changed all that with its graphical user interface and mouse.

"Ordinary people could start to access what computers had to offer just by pointing and clicking icons. In a lot of ways, I'd say the Mac is what really introduced mainstream society to digital life for the first time.

"Even four decades later, you can still see the Mac's fingerprints all over how we interact with technology nowadays."

Costing $2,495 - equivalent to $7,500 now - the first Apple Macintosh featured a built-in screen and mouse and 128kb of memory - a fraction of the size of today's devices.

However, despite the high cost and the idea of personal computers being a relatively new concept, the Macintosh was an immediate hit, selling 70,000 units within the first four months.

It was the first commercially successful personal computer to utilise a graphic user interface (GUI), an idea which had originally been developed by lead designer Jef Raskin, under project Apple Lisa - named after the daughter of co-founder Steve Jobs.

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However, Jobs was pushed off the project amid infighting in the team, leading him to jump across to project Macintosh, which would ultimately prove to be the more successful product.

The success of the Macintosh would pitch Apple against the likes of IBM - the dominant force in the market at the time - and start the company and Jobs on a path towards further innovations, such as the iPhone.

And while Macs, have moved away from the boxy white desktops of the 80s and 90s, they still live on, in the form of much more powerful and streamlined laptops.

A spokesperson for Apple said: "40 years ago Mac revolutionised personal computing and today the Mac line-up continues to push the limits of computing, empowering all kinds of people to do their life's best work."