In a letter to Senators which fell into the hands of CNN, Susan Molinari, VP of public Policy and government affairs at Google confirmed: "Developers may share data with third parties so long as they are transparent with the users about how they are using the data"

The letter, which confirms a story released at the time, goes on to say that any company that is likely to scan your mail has to show its privacy policy clearly before the user grants access or even download the add-on in the first place.

The letter, dated July, says that there is a strict policy against apps that don't make their privacy policy clear or misrepresent themselves.

Google says it is able to suspend apps that subjugate the rules before they do any damage in the "majority of cases"

It does not, however, give any indication of how many apps have been found and removed, but does reiterate that no human reads Gmail messages except in "very specific cases where they ask us to and give consent". This usually means a complaint made to Google about a user.

Next week, the tech giants, including Google, Amazon, Apple and Twitter will be addressing the Senate over increased concerns over online privacy and to examine the safeguards in place to protect consumers.

The news follows an earlier report that shows that third parties are allowed to scan mail for services such as Google Trips, which helps create itineraries for your travel, based on your email content.

Google made no comment to CNN but referred them to a blog post in which it explains the review process, automatic and manual safeguarding, app testing and assessment of policy. It also reminds viewers that they should check the permissions screen when they install, as all the pertinent information is there