The Apple iPad Air 2 has gone on sale in the UK and thousands of customers will be either upgrading or getting into the world of iPad for the first time.

Apple has come along way since the launch of the first iPad in 2010 creating a device today that is far superior to the original tablet.

Looking around the office, we realised that we had virtually all the iPads, from the first iPad, to the thinner follow up, to the iPad 4 (we couldn't find a 3), to the Air launched last year, to the Air 2.

As you can see from the photos, while the front has barely changed (okay so the bezel is thinner now), the noticeable difference is the thickness. Over the last 4 years Apple has managed to shrink the design over and over to the point where the iPad Air 2 is half the thickness of the original model with its bulbous back. It's incredible when you see it there staring back at you.

There are other cosmetic changes too. The iPad's speakers are much better, a Lightning port has replaced the old fat 30-pin connector, and we've got cameras front and back able to snap or let you do video calls.

Inside and it's a hugely drastic experience. The processor in the iPad Air 2 has 180x more graphics power than the original iPad for example. Add to that better connectivity (4G, Wi-Fi, Bluetooth 4), and motion processors (M8) complete with a barometer, and a pin-sharp screen, and you really see what Apple has been doing over the last 4 years.

With all that advancement, just think what the iPad will look like in 4 years time.