The new boss of Apple has marked his first public appearance by launching the company's most expensive iPhone - a foldable handheld that costs at least £1,999.

John Ternus, who took over from long-time chief executive Tim Cook this month, unveiled the iPhone Duo, which is the first major design change to the iPhone for nearly two decades.

Apple is entering the foldable phone market comparatively late, following the likes of South Korea's Samsung and China's Huawei.

Ternus told an audience at Apple's California headquarters: "Others have created foldables that just feel like two phones awkwardly stuck together." Apple's model, he claimed "redefine[s] the experience of using a foldable phone".

In the US, prices start at $1,999, but can go up to $3,200. It has taken eight years to develop, something Ternus was directly involved in after spending many years as a top executive inside Apple's hardware division.

When unfolded, it looks like a small iPad and a wider iPhone when it is folded.

Ternus said: "It's entirely new and at the same time remarkably familiar. A similar size to your passport, it feels familiar to hold and comfortable to use with one hand."

But the product is facing established competitors. "The real fight is China, where Huawei owns nearly 80% of foldables." said Francisco Jeronimo, vice president for data and analytics, devices at IDC EMEA.

Ben Wood, chief analyst at technology research firm FDM CCS Insight, said it was likely Ternus's promotion was timed specifically "to coincide with what will be arguably one of the biggest iPhone launches for many years".

"Nothing happens by accident at Apple," he said.

Carolina Milanesi, an analyst at Creative Strategies who attended the Wednesday presentation, said the spotlight on Ternus made it feel "almost like he was a product himself."

Altering the design of the iPhone may address some criticism that Apple has yet to land a major product hit or truly exciting innovation since the first iPhone came out in 2007.

"The foldable risks becoming a premium-priced ornament in the portfolio, imparting badge value but not meaningful growth," said Dipanjan Chatterjee, an analyst at Forrester.

Previously, the highest starting price of the newest iPhone was $900 (£664).

Apple also revealed on Wednesday the new iPhone 18 Pro and 18 Pro Max, which in the US start at $1,199 and $1,299 respectively.

Chatterjee said the foldable iPhone could go the way of Apple's Vision Pro headset, which the company priced at $3,699 and has not been a hit with buyers.

Or, he said, it could be the company's next Apple Watch which, while not as popular as the iPhone, is bought by millions of people each year.

The way people have become accustomed to the way the iPhone operates is another potential hurdle to Apple seeing big sales of the new design.

"Foldables are interesting devices", Milanesi noted. "A lot of people are intrigued by it, but the software and the learning curve that you have from moving from a traditional phone to a foldable is real."

Wood noted that the current market for foldable smartphones from the likes of Samsung and Huawei make up only 2% of smartphone sales. Even with Apple's version likely driving interest and demand, sales are only expected to reach 4% of the total market in the next decade, according to data and analytics firm FDM CCM Insight.

The iPhone has been Apple's top-selling product and accounts for more than half of the company's sales each year.

In recent quarters, the company has boasted that the iPhone is more in-demand than ever, with the most recent version of the device becoming its most successful product launch.

The company also revealed more about the coming relaunch of its audio and chat assistant Siri, which it now calls Siri AI.

Starting with the iPhone 18, the bot will now be able to go across information on a person's phone, like messages and emails, to find information, answer queries and take action on a person's behalf.

Some Siri AI features will also be available on the new Apple Watch, including the ability to take notes of conversations and transcribe them, should a wearer enable that feature.

Ternus referred to new AI-enabled capabilities on the iPhone as an "intelligent personal hub", and admitted that Apple would be making use of "the most private details of your daily life."

He insisted that all of it will remain private, with the AI features often running "on device", meaning not through third-party companies. And when a third-party is required for a function, Ternus said it will remain private in a remote server, or cloud.

"Others see that data as something to collect and store", Ternus said. "Here, not even Apple can access what's yours."