the key differences for iPad 3 and for iPad 4:

Camera for iPad 3 and for iPad 4:

Pad for iPad 3 came with a 0.3MP standard definition offering, whereas the iPad 4 makes full use of the Retina display for video chatting with a 1.2MP HD camera.

Processor iPad 3 and for iPad 4:

Gearing up from the iPad 2, the iPad 3 comes rocking a dual core A5X processor, with a quad core GPU. However, the iPad 4 packs Apple's latest A6X processor, which Apple says "doubles the performance of CPU tasks."

Learn more: iPad 4 more than twice as fast as iPad 3, benchmarks reveal

OS for iPad 3 and for iPad 4:

Apple's latest operating system, iOS 6, was recently launched alongside the iPhone 5, so unsurprisingly it's also featured on the iPad 4. The iPad 3 launched with iOS 5.1 but is upgradable to iOS 6.

Connectivity iPad 3 and for iPad 4:

The big difference between the two iPad generations lies within their connectivity options. The most obvious of these is the new 8-pin Lightning dock, first announced on the iPhone 5.

Old and new, left to right

This is 80 percent smaller and more durable than Apple's original 30-pin offering.

The other major difference is that the iPad 4 (Wi-Fi + Cellular version) comes LTE enabled. The iPad 3 did come enabled with 4G, however, it couldn't be used in the U.K. But, with the introduction of the iPad 4 Brits can also enjoy super fast mobile internet when they're out and about.