Pornography will be the main driver of third-generation (3G) mobile services demand, according to the chief executive of adult entertainment company Private Media Group.

Porn mogul Charles Prast told Reuters that, while phone companies try to decide what the killer application will be for 3G, his company is convinced that sex is the answer.

"In new technologies, adult services usually account for 80 per cent of traffic. It has been so with video, the internet and DVD. It is natural to assume it will be the same with mobile internet," Prast is quoted as saying.

But he predicted that, once 3G becomes established, porn use will drop to about 20 per cent of overall traffic.

Analysts estimate that the value of the pornography market will be $70bn (£44bn) in 2006, and that $4bn (£2.4bn) of that could come from mobile services.