Android apps, including some from the Top 50 list, are sending users’ personal information to third-parties without their permission, an investigation carried out by Channel 4 has revealed.

The research, carried out by MWR InfoSecurity, found that once a user has granted permission for an app to access certain information, that permission is also passed to third party advertisers. Users are not made aware of this, the research says.

"We found that a lot of the free applications in the top 50 apps list are using advertising inside the applications, and that the permission that you grant to these applications is also granted to the advertiser," MWR InfoSecurity told Channel 4.

"If users knew about this, I think they would be concerned about it," the company added. "But at the moment I don’t think they are aware of the situation and how widely their information can be used."

The company discovered code within apps that gave advertisers access to a user’s contacts, calendar and location. Potentially any data the app is able to access can be sent on to a third party.

Channel 4 claims the advertising company involved is called MobClix; CBR has requested comment from the firm, which is part of Velti, but had not heard back at the time of publication.

The apps could potentially break European data protection laws. Viviane Reding, vice-president of the European Commission, told Channel 4: "This really concerns me, and this is against the law because nobody has the right to get your personal data without you agreeing to this."

"They are spotting you, they are following you, they are getting information about your friends, about your whereabouts about your preferences," Reding added. "That is certainly not what you thought you bought into when you downloaded a free-of-charge app. That’s exactly what we have to change."

Google does not screen apps before they are made available on its Android Market app store, which has led to an increase in the number of rogue apps available. A recent report by Kaspersky Lab revealed a huge rise in malware aimed at the Android operating system. Most of these seem to be apps that sign the unwitting user up to expensive text messaging service.

Google had not responded to CBR’s request for comment at the time of publication.