iPhone, Android spy on users with secret ad tracking -

While Jobs' Mob has been particularly good at censoring apps that rival its business, it has been less successful at blocking those which spy on users.

Some apps, such as music identifying software Shazam, have Apple's blessing. Another app which spies on you is the hugely popular Angry Birds.

The research by the Daily Mail found that smartphone users had no way of stopping the tracking details of movements online and off, which are given to advertisers who then flood you with personalised adverts.

Out of 101 apps tested, 56 transmitted the phone's individual number to a private company in some way, known as the Unique Device Identifier or UDID.

Nearly half sent the phone's location and five sent age, gender and other personal information.

The iPhone was much worse than Google's Android, although both Apple and Google have promised not to let such practices take place.

Michael Becker of the U.S. based Mobile Marketing Association shrugged and said that in a moble world advertisers are "always with us."  He said there is no anonymity.

Apple spokesman Tom Neumayr insisted that Apple had created strong privacy protections for its customers, especially regarding location-based data. He said that 'privacy and trust are vitally important' which is shorthand for 'trust us, we will not harm you'.

The question is how you can trust either Google, which has been in serious privacy offence territory, or Apple to look after you.

The report showed that Angry Birds sent the phone's UDID to Electronic Arts.

Pandora sent gender, location age and the phone ID to a string of advertising networks.

Both Android and iPhone versions of a game called Paper Toss, where players try to throw paper wads into a bin, each sent the phone's ID number to at least five ad companies.

A Google spokesman admitted its AdMob wing targets adverts based on information gleaned from apps.