The FTC claimed Google had previously told Safari users that the browser’s default block on third-party cookies made it unnecessary for them to actively opt-out of Google’s own advertising tracking cookie.

However, it is alleged that Google “exploited an exception to the browser’s default setting to place a temporary cookie from the DoubleClick domain” which then “opened the door to all cookies from the DoubleClick domain” including the advertising tracking cookie Google said would be blocked. DoubleClick is Google’s ad serving technology platform.

The size of the fine is the largest ever for an alleged violation of a commission order. Since 2011, an FTC order has barred Google from misrepresenting the extent to which consumers can exercises control over the collection of their information.

FTC chairman Jon Leibowitz said: “No matter how big or small, all companies must abide by FTC orders against them and keep their privacy promises to consumers, or they will end up paying many times what it would have cost to comply in the first place.”

Google has not admitted to any wrongdoing as part of the settlement and online commentators have pointed out that the fine is less than the company’s average daily profit, based on 2011 figures.