The Competition and Markets Authority said the investigation will assess whether the proposals could cause advertising spend to become even more concentrated on Google’s ecosystem at the expense of its competitors.

The search giant announced it will no longer allow so-called third-party cookies, or digital trackers that follow people’s activities across the internet, to be used on its popular Chrome browser from 2022 onward.

The decision means that a publisher, for instance, would no longer be able to collect information about its readers on other websites via these trackers if its readers rely on Chrome, which is used by one out of every two web users outside China.

The move, which has been billed as privacy-boosting, follows increased scrutiny of such data-harvesting techniques in the European Union and California, which have both revamped privacy standards to limit how much digital information can be collected, stored and used on web users from Sacramento to Strasbourg.

Google also opens itself to potential accusations that it will favor its own data hungry services over those of competitors.

The search giant is, with Facebook, one of the world’s most powerful players in online advertising, and will continue to collect and use data gathered on users as part of its global online advertising business.

That could amount to a major advantage over advertising rivals that would eventually find themselves shut out of the Google's dominant browser, and bolster the tech company's already prominent position in an online advertising industry worth hundreds of billions of dollars annually.