After years of rumour and speculation, Apple has finally revealed its first folding smartphone. Called the iPhone Duo – a name few saw coming – the new handset is broadly passport-sized, with a 5.4in display on the outside and a 7.6in screen within.That’s the largest display ever fitted to an iPhone, and is only just short of the iPad mini. The Duo features a chassis made of polished titanium, while its clever hinge mechanism has more than 100 parts to ensure the screen folds neatly in half with a barely perceptible crease at the centre.When The Independent’s tech editor Andrew Griffin got hands-on with the device in California, he was, much to his surprise, impressed. It is “just so satisfying to open and close”, he wrote in his first impressions review. “Once the device is actually open, the unfolded screen is beautiful. There’s no visible crease at all: if you didn’t know it could fold, you would never guess the iPhone Duo wasn’t just a new iPad Mini,” he added. The iPhone Duo, in the hand (Andrew Griffin/The Independent)While still an iPhone at heart, the iPhone Duo runs a modified version of Apple’s new iOS 27 operating system, complete with software animations and transitions unique to this model. “Apple has done an astonishing job in ensuring that the phone knows it is opening, and mirrors the content on the little screen onto the big one, so that you almost forget they’re not actually the same thing,” noted Griffin. It’s a bold new phone for Apple, and arguably the biggest hardware evolution in the 19-year history of the iPhone. But all that clever folding tech comes at a cost, with the iPhone Duo starting at £1,999 for 256GB of storage. Ahead of its launch, we’ve detailed all the key pre-order details. Read more: Best refurbished iPhone deals When can you pre-order the iPhone Duo in the UK?Apple revealed its iPhone Duo on 9 September. The folding phone will arrive slightly after the equally new iPhone 18 Pro and Pro Max. Pre-orders open for the Duo in the UK at 1pm on Friday 16 October. It’ll then be available to buy online and in-store from Friday 23 October.The iPhone Duo costs £1,999 for the 256GB model, £2,199 for 512GB, £2,599 for 1TB and £3,199 for the 2TB model. The folding phone will also be available interest-free from Apple, from £66.63 per month for 30 months.Apple’s trade-in system lets you hand in an old iPhone and receive a refund on your iPhone Duo purchase of between £25 and £855 depending on the model and its condition.What iPhone Duo contract deals will be available? Phone carriers won’t reveal their pre-order deals for some time. As it’s a completely new handset, it’s tricky to predict how much a contract will cost. Looking back to the iPhone 17 Pro Max won’t even provide enough insight into what we might see, as the Duo is more expensive. But at Sky, the iPhone 17 Pro Max started from £38 per month. We’ll keep this page updated with all the latest information as soon as we get it. iPhone Duo specs The iPhone Duo is Apple's first foldable phone (Apple)Available in night sky (dark blue) and star white (glossy white), the iPhone Duo breaks new ground for Apple, but comes seven years after rivals like Samsung began experimenting with early folding smartphones. The Duo’s internal screen is 80 per cent larger than that of the new iPhone 18 Pro Max, while even the smaller exterior display has more than 90 per cent of the screen area of the iPhone 18 Pro.Apple’s new flagship phone foregoes Face ID in favour of a Touch ID fingerprint scanner on the side-mounted power button. And while the Duo has a 12MP selfie camera on the inside screen, it has cleverly been hidden behind the display, removing it from view when not in use.When folded open in landscape, the iPhone Duo can display two apps side by side, bringing true multitasking to an iPhone for the first time. Held open in portrait, the screen can be split horizontally, displaying a widescreen video above a messaging app or web browser, for example. “When you see someone using the iPhone Duo, the central feature of using two apps side-by-side can seem a little convoluted, requiring all kinds of precise flicking and organisation. But when your fingers are actually on the screen, and you’ve done that a couple of times, it becomes second nature within seconds,” wrote Griffin. If partially opened and stood up like a tent, the iPhone Duo automatically launches StandBy mode, clock, calendar or other useful information. Set an alarm, and the interior screen glows like a brightening sunrise at your bedside. But you can also bend it like a tiny laptop and the phone adapts to it. “Overall, the whole hardware and software experience is so deeply integrated that the folding nature of the phone stops feeling strange very quickly. Within a few minutes of using it, it just felt sort of inevitable, and like I wanted one,” added Griffin. As for battery life, Apple claims the iPhone Duo can play video for up to 31 hours on the larger inner display, or up to 44 hours on the smaller outer screen. Fast charging promises a refill to 50 per cent in around 20 minutes with a compatible charger.Pre-order from 16 OctoberiPhone deals If you’re not sold on spending £1,999 for the iPhone Duo but need to upgrade, retailers are starting to slash the price of previous iPhone models. The price of the iPhone 17 Pro has been cut at many retailers (David Phelan/The Independent)For an iPhone 17 Pro, I’ve seen the price drop from £1,099 to £999 at Very, Currys, John Lewis and Amazon. Affordable Mobiles currently has one of the cheapest iPhone 17 Pro deals. You can get the phone with 100GB of data for £49 per month and a £39 up-front cost.