One of the most talked about rumours regarding the iPhone 6 is its size. Will Apple make a bigger iPhone? Only time will tell, but here, we've gathered the evidence to bring you everything we know about Apple's rumoured bigger iPhone, also sometimes referred to as the iPhablet, as well as some concept images and leaked parts.

A bigger iPhone has been hot topic for a while now, especially as bigger smartphones with larger screen sizes have grown in popularity. The iPhone is one of the smallest high-end smartphones now available, with some 'mini' or 'compact' versions of popular smartphones even sporting bigger screen sizes than Apple's iPhone 5s and iPhone 5c.

There is also a growing trend for 'phablet' devices, which fall between a smartphone and a tablet. They range in size, but are usually around 6in, with Samsung's Galaxy Mega actually boasting a whopping 6.3in display.

Not everyone's keen on the idea of a bigger iPhone, however, and many argue that the 4in display that can be controlled with just one hand is a huge selling point for the iPhone. But it has become clear that bigger iPhones are growing in popularity so we'd be surprised if Apple didn't launch an answer to that trend soon.

Here, we've rounded up all of the speculation, images and rumours about the bigger iPhone, and discuss the question of whether the bigger iPhone will be Apple's next flagship or a whole new launch to expand the iPhone line-up.

We won't know for sure until we hear confirmation from Apple itself, but for now, we can weigh up the evidence to give us some clues as to what a bigger iPhone might be like. Apple hasn't kept completely quiet about a bigger iPhone, though. Read on to find out what the company's executives have been saying.

What Apple has said about a bigger iPhone

Apple CEO Tim Cook hasn't ruled out the possibility of a bigger iPhone. In April 2013, during Apple's quarterly earnings call at the time, Cook said: "My view continues to be that the iPhone 5 has the absolute best display in the industry. We always strive to create the very best display for our customers."

"Some customers value large screen size, others value also other factors such as resolution, colour quality, white balance, brightness, reflectivity, screen longevity, power consumption, portability, compatible apps, many things," Cook continued.

"Our competitors have made some significant trade-offs in many of these areas in order to ship a larger display," Cook said. "We would not ship a larger-display iPhone while these trade-offs exist."

During the D11 conference the following month, Cook repeated his thoughts about a bigger iPhone. "A large screen today comes with a lot of trade-offs," he said. "Customers are clearly looking at size, but they also look at things like: 'Do the photos show the proper colour?' the white balance, the reflectivity, battery life, brightness, the longevity of the display. There are a whole bunch of things that are very important."

It's likely that Apple is hard at work trying to banish those trade-offs in order to launch a top-quality iPhone with a bigger display at some point. After all, it has been almost a year since Cook said those things.

Since then, Cook has dropped a few hints about the future of the iPhone, and some of those suggest the future is indeed bigger.

In December, Cook wrote that Apple has "big plans" for 2014, which we think could be a sneaky hint at a bigger iPhone.

Cook has also said that he believes there are significant opportunities for Apple to expand the position of products such as the iPhone, and had noted that his statement that Apple doesn't aim to make the most smartphones has been misunderstood, again hinting that an all-new iPhone could be on its way to join the iFamily.

Further evidence from Tim Cook that suggests we're going to see a bigger iPhone this year comes in the form of a puzzling comment from the Apple CEO. When talking about his promise to introduce products in new categories, Cook said that any "reasonable" person would consider what's on the cards as a venture into a new category. If Cook was talking about an iWatch or Apple television, it's unlikely he would have felt the need to specify that not everyone will consider the new product part of a new category, which hints that it may in fact be a bigger version of Apple's iPhone.

Should Apple release a bigger iPhone?

Not everyone thinks Apple should release a bigger iPhone, but I for one really do, as I've talked about here. I'm not alone in that opinion, either, though I'm hoping that Apple doesn't go as far as making the new iPhone a phablet.

Barclays Capital analyst Ben Reitzes has said that Apple needs to launch a bigger iPhone because he expects the larger phone market to dominate smartphone shipment growth into 2015.

When Apple launched the iPhone 5 with a bigger display, Apple explained that the reason for increasing only the iPhone's height and giving the iPhone a 4in display was to ensure that it could be used with one hand. Reitzes says that the one-handed use of the iPhone will be "less important since phone calls are becoming less important than navigation, texting, videos, books and web access for many."

Bigger iPhone release date

Most reports predict a 2014 launch for a bigger iPhone. Reports from the likes of Digitimes, the Wall Street Journal, and analysts have all pointed to the launch of a bigger iPhone this year.

There has also been some speculation to suggest that the bigger iPhone will arrive in the first half of 2014 before a second, 4in iPhone later in the year.

A note from previously accurate KDB Daewoo Securities released in February claimed that Apple is indeed working on two new iPhones, but that both of those will be significantly bigger than the current iPhone.

Oddly, the report suggests that, rather than launching with iOS 8 installed, both devices will be running iOS 7.2, which again hints at an earlier than September launch.

What size will the bigger iPhone be?

The actual size of the bigger iPhone has been widely debated. Many reports suggest a size of around 4.7 or 4.8 inches, while some others suggest an even bigger iPhone with a 5.7in display is on the cards, perhaps in addition to the 4.7/4.8in device.

KDB Daewoo Securities has shared some alleged resolution specifications of the bigger iPhone, too. It claims the smaller of the two rumoured devices will have a 1,920 by 1,080 pixel display (468ppi) while the phablet will have a 2,272 by 1,280 pixel display (474.14ppi). By comparison, the iPhone 5s has a pixel density of 326ppi.

There is also talk of quantum dot technology being used in the bigger iPhone, which would improve colour accuracy of the display – one of the trade-offs Cook mentioned.

Will the iPhone 6 be a bigger iPhone, or will Apple launch two new iPhones this year?

The consensus around the web seems to conclude that Apple is unlikely to get rid of a 4in iPhone option. Here at Macworld, we'd like to see Apple release two new iPhones this year, a new flagship smartphone that is a successor to the iPhone 5s and likely called iPhone 6, as well as a bigger option for those who want an iPhone with a larger display.

The launch of the iPhone 5c, and also the iPad mini, proved that Apple is no longer adverse to introducing more than one size of device in each line-up, so we think Apple would be wise to keep both a smaller and larger version of the iPhone to avoid upsetting fans of the smaller form factor.

Bigger iPhone rumours: Sapphire display & Liquidmetal

In order to achieve a bigger iPhone, Apple may use sapphire for the glass screen, liquidmetal for the chassis and thinner bezels to keep the overall size of the device to a minimum.

Apple's Sapphire plant in Arizona could be used to manufacture 200 million 5in iPhone displays per year, according to reports that emerged in February. Recently published documents revealed that Apple and manufacturing partner GT Advanced Technologies are aiming to open the new plant in Arizona this month, and Apple CEO Tim Cook has confirmed that the plant is indeed for sapphire glass, as previously rumoured.

Sapphire glass is more durable than Gorilla Glass, so could be an ideal material to use for the bigger display.

Liquidmetal is also said to be more durable than aluminium, and therefore can be used in smaller quantities to be as strong as the metal used for Apple's current iPhones. This would enable Apple to keep the bigger iPhone light and thin, despite the bigger screen.

Plus, removing the bezels in the bigger iPhone to create an edge-to-edge display would mean Apple could introduce a bigger display without the need to increase the overall size of the iPhone too much.

Bigger iPhone leaked images

The first leaked image of a bigger iPhone (above) hit the web on 8 January, though many publications have rubbished the photograph, suggesting that it's unlikely to be a genuine leaked part. We're inclined to agree for several reasons, including the fact that it appears to be a midframe part that is no longer found in Apple's iPhones as the iPhone 5 uses a unibody design. You can see the image for yourself below.

Concept images of the bigger iPhone have also emerged, including the image at the top of this article created by Nikola Cirkovic.

A new concept spotted on ConceptsiPhone and created by Joseph Farahi includes several well-rendered images and a video that shows a 5.1in iPhone 6. It's thinner, has a higher-resolution display, and also has solar charging capabilities.

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