Those Apple iPad users investing in a new iPhone 4 may be disappointed to discover you won't be able to share the smartphone's micro-SIM card to get online.

In an new Apple FAQs the company states: "Are iPhone 4 and iPad micro-SIM cards interchangeable? No. Your iPad micro-SIM card will not work with your iPhone."

However, a spokesperson for O2, one of Apple's partners for the iPhone and iPad in the UK, told PC Pro the devices are "quite different."

"Both use a mini-SIM, but the iPad micro-SIM is not, for example, provisioned for voice, and focuses on flexible data. The micro-SIM for the iPhone is set up for voice and other functionality."

Apple iPhone 4

The iPhone 4 goes on sale next Thursday, 24 June in the UK, US, France, Germany and Japan, with reports that stocks may already be limited. Currently, O2, Orange, Vodafone, T-Mobile, Three and Tesco Mobile will all be selling the iPhone 4 at launch in the UK.