Car Bluetooth systems are more stable than most mobile phones or computers, it has emerged.

In response to an <link rel='prefetch' href='' SC story suggesting a mobile phone virus had infected a Toyota Bluetooth system, Finnish antivirus firm F-Secure took one 50 metres under the sea and tested it out.

"We expected it to get infected, but the actual results were more interesting," said Mikko Hypponen, director of anti-virus research at F-Secure. "The bottom line is the Toyota we tested could not be infected by any of the current Bluetooth viruses."

The company's weblog details the underground bunker and the car which, after hours of battering with Bluetooth connections, eventually succumbed to a low battery rather than a mobile virus.

"We managed to find one minor issue with the system (a corrupted phone name would freeze the on-board display), but otherwise the Prius Bluetooth system was far more stable than our test phones and PCs," said Jarno Niemela, a virus researcher writing on the company's weblog. "We had to reboot our test systems several times as their Bluetooth systems died on us, while Toyota Prius just kept going."

The SC article caused a great deal of brouhaha in late January and prompted a swift response from Toyota.

Around the same time SC reported an IBM claim that viruses hitting satellite systems and cars was, in fact, inevitable.