While computer viruses are almost exclusively the work of organised criminals, mobile viruses are largely the work of amateurs, according to an industry expert.

Kimmo Alkio, chief executive at F-Secure, told vnunet.com that mobile viruses encountered by his company rarely bore the hallmarks of organised criminal gangs.

This stands in stark contrast to the well documented use of worms and Trojans in PCs to build botnets and steal information by identity theft.

"We believe that mobile viruses are still created mainly by hobbyists," said Alkio. "Criminal attacks are a tiny proportion of mobile virus attacks."

Alkio believes that there are two principal reasons for this. Firstly, the number of smartphones capable of holding information that could be used for financial gain is still relatively small compared to the overall user base of mobile phones. This makes them a relatively unattractive target.

Secondly, there is no monoculture of operating systems in the mobile sphere. European phones are largely Symbian-based while US smartphones predominantly use Windows Mobile.

This is in contrast to the PC market where around 85 per cent of PCs use Windows, with the rest split between Apple and open source code. This makes it easier to write a virus for a PC that is likely to be productive.

"Organised criminals have realised that mobile viruses are not the best way to make money," said Graham Cluley, senior technology consultant at Sophos.

"Why bother to write a mobile virus when PC ones make more money? Meanwhile amateurs are writing viruses for bragging rights; the infections are relatively rare and they might get a story to show their friends."

In the longer term, as phones get more powerful and smartphones more pervasive, this may change. But Cluley noted that this has not occurred as fast as many had predicted.