Like millions of people, Tim Cook stopped wearing a watch a while ago. The Apple boss no longer needed one: his iPhone told the time just fine. There was just one problem — glancing at one’s wrist can be a very useful way to find out information.

It is less rude and less intrusive. So Apple now wants to pull off something that no company has managed before: reversing a cultural trend that it created itself. It wants us to start wearing watches again.

A big launch event on March 9 will showcase the Apple Watch and it will be released to consumers in April. Cook, needless to say, is already wearing his. “I’m now so used to getting all my notifications and all my messages,” he says. “It’s so incredible just to do this.”

The first reason to buy the watch will be as a fashion statement and for its striking design. The watch has also been designed and engineered to be a highly accurate timekeeper: it will be correct to 50 milliseconds, he promises. But when consumers witness the Apple Watch’s full potential for themselves, Cook says, they will understand just how different it is from a traditional watch or from any other existing device.

The chief executive has a product to sell, of course, but his enthusiasm is contagious. Sceptics are quickly intrigued. Like Steve Jobs, he clearly lives and breathes his business. He is charismatic, eloquent and switched-on.

“This will be just like the iPhone: people wanted it and bought it for a particular reason, perhaps for browsing, but then found out that they loved it for all sorts of other reasons.”

Cook expects an explosion of new apps for the Apple Watch. One of its great missions will be to harness technology to help improve users’ health. The Apple Watch will, of course, be able to monitor heart rates, Cook says, using special sensors on the back of it, but it will be far more sophisticated than that.

It is bad for people’s health to sit still too much; so the watch will gently tap the wearer’s wrist every hour to remind them to stand up and go for a walk if they haven’t had enough exercise. To some couch potatoes, this might sound like a nightmare; but many others will undoubtedly embrace the idea’s revolutionary potential.

Even more intriguingly, the watch will operate a rewards system: users will get credits if they exercise enough. They will also be encouraged to increase their metabolic targets if they meet their exercise targets consistently. Consumers will clearly have an incentive to wear the watch for as much of the day as possible, and even in the shower.

There will be lots of other potentially game-changing uses. The watch is designed to be able to replace car keys and the clumsy, large fobs that are used by many vehicles, Cook says. This could be a major development and will reinforce the view that Apple is circling an automotive market ripe for radical disruption.

Another major application will be for paying: the Watch will be able to serve as a very usable digital wallet, courtesy of Apple Pay, which allows customers to pay for goods with a touch of their iPhone, or Apple Watch. The system will be ultra-safe, Cook says, certainly more so than credit cards.

Another breakthrough is that Apple Watch will better filter messages, Cook says. It will make it much easier to prioritise, spot and react to urgent messages. These notifications will be much easier to deal with via one’s wrist than through an iPhone, especially in meetings. The watch’s battery life will last the whole day, and it won’t take as long to charge as an iPhone.

The launch of the watch will undoubtedly pose a challenge for Apple’s stores. “We’ve never sold anything as a company that people could try on before,” he says. This may require “tweaking the experience in the store”, he told his staff at the company’s Covent Garden shop.

He speaks extremely highly of Angela Ahrendts, the former Burberry boss who now runs the stores and has been tasked with making the online and bricks-and-mortars elements work seamlessly. Crucially, Cook believes that the Apple Watch will help create a new blockbuster product category. There are already smartwatches on the market, just as there were MP3 players before the iPod and smartphones before the iPhone.

But he believes that the Apple Watch will revolutionise the market and become “the modern smartwatch” — the only one anybody wants to buy. But while the Apple Watch is Cook’s great personal gamble and could define his time in the role, it is not the only subject that he is passionate about.

He is a radical privacy advocate and was on the last leg of a trip to Europe where he discussed this issue extensively. Cook said that it was clear that there were many instances of people’s information being “trafficked around” and that this was something his company abhorred.

At the moment, however, consumers often “don’t fully understand what is going on. One day they will, and will be very offended”. Apple’s views on the subject stand in stark contrast to the position taken by Facebook and most other US tech giants, which are much more relaxed about these issues.

Cook disagrees fundamentally. “None of us should accept that the government or a company or anybody should have access to all of our private information. This is a basic human right. We all have a right to privacy. We shouldn’t give it up. We shouldn’t give in to scaremongering or to people who fundamentally don’t understand the details.”

The Apple boss is also prepared to connect his battle with past horrors; he could not be any more emphatic. “History has taught us that privacy breaches have resulted in very dire consequences. You don’t have to look back too far or be a historian to see these things. They are readily apparent.”

But what about the threat of terrorism? The Apple boss is clearly no softie or apologist on the matter. “Terrorism is horrible and must be stopped. All of us must do everything we can do to stop this craziness.” He adds that “these people shouldn’t exist. They should be eliminated”.

Yet he does not accept the view that privacy needs to be compromised to combat the killers. There is no trade-off, in his view, because the terrorists already use their own encryption tools, which cannot be controlled by the UK or US. So forcing the likes of Apple to make their consumers’ data freely available to the authorities would do nothing to protect the public in the West.

“Terrorists will encrypt. They know what to do. If we don’t encrypt, the people we affect [by cracking down on privacy] are the good people. They are the 99.999 per cent of people who are good.”

Without encryption, coding data so only authorised parties can read it, he believes that the public’s private financial, health and personal information, which is increasingly kept on mobile devices, would inevitably “be taken”.

Cook’s concern does not merely extend to governments: he does not want big private companies to be able to snoop either. “If you want to keep your health personal, you shouldn’t have to share it with your insurance company. These things are not meant to be on some bulletin board somewhere.”

Privacy is central to Apple’s principles, Cook argues, and he is clearly prepared to fight on this issue.

“You don’t want to eliminate everyone’s privacy. If you do, you not only don’t solve the terrorist issue but you also take away something that is a human right. The consequences of doing that are very significant.”

This philosophy has had a number of consequences for the way Apple conducts its operations and how it makes its money. “Apple has a very straightforward business model,” he says. “We make money if you buy one of these [pointing at an iPhone]. That’s our product. You are not our product. We design our products such that we keep a very minimal level of information on our customers.”

It also means that Apple’s strategy has made it less profitable than it otherwise might have been, at least in the short term (and even then few shareholders are likely to have noticed, given its massive cash pile).

“We don’t make money selling your information to somebody else. We don’t think you want that. We don’t want to do that. It’s not in our values system to do that. Could we make a lot of money doing that? Of course. But life isn’t about money, life is about doing the right thing. This has been a core value of our company for a long time.”

Needless to say, Cook obviously thinks that his firm will do better, including financially, over time if he follows such values, especially if the public wakes up to just how easy it is becoming to obtain personal information; although he does not actually say so, doing good and doing well in the long run presumably go hand in hand in his mind.

“The issue becomes when you begin to observe everything people are doing: read their emails, read their messages, monitor their browsing habits, really study everything about them and then connect the dots about these things.” Relatively minor pieces of information, added together, become greater than the sums of their parts.

“Some companies are not transparent that the connection of these data points produces five other things that you didn’t know that you gave up. It becomes a gigantic trove of data.”

— The Telegraph Group Limited, 2015.