The first worm to infect the Apple iPhone has been discovered spreading "in the wild" in Australia. 

Some estimates suggest that up to 10% of all iPhones and iPod Touch are jail-broken.

The self-propagating program changes the phone's wallpaper to a picture of 80s singer Rick Astley with the message "ikee is never going to give you up".  The worm, known as ikee, only affects "jail-broken" phones, where a user has removed Apple's protection mechanisms to allow the phone to run any software.  

A spokesperson for Apple warned against jail-breaking handsets. "These hacks not only violate the warranty, they will also cause the iPhone to become unstable and not work reliably," the spokesperson said. The practice allows a phone user to install software and applications that have not been approved by Apple.  "Phone users may rush into jail-breaking their iPhones in order to add functionality that Apple may have denied to them, but if they do so carelessly they may also risk their iPhone becoming the target of a hacker," said Mr Cluley.  

Currently the worm is only circulating in Australia which is where its creator lives and it can be removed by changing the phones password and deleting some files.  However, the problem has raised questions over security and some fears about more malicious attacks like this in the future. 

The picture of Rick Astley is believed to be a nod to the internet phenomenon known as Rickrolling, where web users are tricked into clicking on what they believe is a relevant link, only to find that it actually takes the user to a video of the pop star's song "Never gonna give you up".