ICSTIS, the UK's premium rate phone watchdog, has given a cautious welcome to Jamster!'s decision to let parents prevent their kids from downloading content from its website.

The Jamster! Guardian service goes live in the UK this week and rolls out to other countries later this year. It enables parents enter a mobile phone number onto the Jamster! website to prevent content from being downloaded to that phone.

A spokesman for ICSTIS said the regulator welcomed the move before adding that there "was not enough detail to comment further".

Jamster! - a wholly-owned subsidiary of VeriSign - supplies mobile content such as ring tones, music, graphics, and games to mobile phone users.

And while the mobile content market is booming, there are concerns that people buying ring tones for aren't completely aware of the small print. In some cases, for example, punters believed they were buying a single ring tone when they were actually subscribing to a service that cost them money each time they were sent a new tune.

And since many of the service on offer appeal to young people, it is parents who have to pick up the bill.

Announcing the measure today Jamster! COO Markus Berger de León said he wanted parents "to feel comfortable and confident" in how their families use Jamster!'s content. ®