Google’s plan is to ditch third-party cookies in its Chrome web browser in favour of its own “privacy sandbox”. Traditional third-party cookies allow advertisers to track individuals across the websites they visit to serve them personalised ads outside of Google’s ecosystem.

The new system will split users into cohorts, and rather than a person’s browser history being sent to a central location, their own computer will figure out what they like and assign them to a group with similar interests.

Online ads will still be personalised under the system, but Google claims it will afford users greater privacy.

With Chrome capturing around 65 per cent of the global browser market, the CMA has expressed concern that the sandbox will create a walled garden of sorts that will “cause advertising spend to become even more concentrated on Google’s ecosystem at the expense of its competitors”.

Now it has said it will take up a role in the design and development of...