Many of the top 50 free apps in the Android marketplace contain a computer code that leaks highly private data such as contact lists to advertisers.

According to the Daily Mail, apps such as a free version of popular game Fruit Ninja contain secret code that leaks highly private data to advertising network MobClix.

Data privacy company MWR Security has revealed this.

Users agree to the app having access to phone functions – but not to this information being passed to advertisers.

It’s not clear what this data is being used for, or whether it is stored remotely.

A quarter of all mobile phone users in the UK use Android.

In January alone, 100 million Android apps were downloaded in the UK.

Benjamin Cohen of Channel 4, which conducted the investigation said, ‘Channel 4 News tried to speak to MobClix, which is part of a large, Nasdaq-listed company, Velti, over the course of the week, on multiple occasions but we’ve not received an answer to what they are doing with this data or if they are storing it.’

Viviane Reding, Vice President, European Commission said: “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.”