Google has admitted using forbidden APIs to get its iPhone application working, but despite that admission the application remains available on iTunes in apparent breach of the store rules.

Apple provides documentation on the APIs (Application Programming Interfaces) that developers are allowed to use, and restricts access to others for reasons they are under no obligation to reveal. The specific API used by Google Mobile Search gives access to the proximity sensor that the app uses to detect when the handset is lifted against the face - and thus when it should start recognising speech.

Illegitimate use of the API was suspected by other developers, and was confirmed to C-Net yesterday.

Officially such applications shouldn't be allowed in the iTunes store, but it seems the rules don't apply to everyone as Google Mobile Search remains available.

Apple has already been pretty arbitrary about how it applies the rules on listing applications - such as blocking MailWrangler on the grounds that it would confuse users, then allowing BdEmailer, apparently because the latter application is a write-only email app and therefore won't confuse anyone. Other applications have been removed on even more indiscernible grounds, such as featuring a picture of a knife.

But while those rules have been arbitrary and largely unknown, they have so far been applied equally to all - even Google was forced to wait while its app went through the approval process. Now, however, it seems that if you're Google then not all the rules apply to you. ®