The Information Commissioner’s Office, Britain’s privacy regulator, said it would launch a formal investigation after Google did not bow to European pressure to reverse the changes.
By tracking behaviour and across more of the web, it aims to build a more detailed profiles of individuals' interests to enable it to target advertising more accurately.
Previously, data from separate Google services was held and used separately. Google went ahead with the overhaul despite protests led by the French privacy watchdog, CNIL, on behalf of regulators across Europe, including in Britain.
Today the Information Commissioner’s Office said a formal investigation would go ahead.
“The action follows an initial investigation by the French data protection authority CNIL. Several data protection authorities across Europe are now considering whether the policy is compliant with their own national legislation.
“As this is an ongoing investigation it would not be appropriate to comment further.”
The regulator has powers to impose fines of up to £500,000 on companies that flout the Data Protection Act. It can also issue enforcement notices to compel transgressors to change their policies.
Such an order could mean major engineering work and costs for Google.
CNIL had given Google four months to respond to its initial investigation. It found the new policy did not give individuals sufficient control over how they were being tracked online. Google had also not gained full consent to combine personal data, CNIL said, and refused to provide full details of how long it would be held.
Today the French regulator said Google “has not implemented any significant compliance measures” and that it had set up an inspection procedure, as well as links between national regulators investigating the alleged law breaking.
Last year CNIL urged the firm to delay implementing the new policy, but was ignored.
The campaign group Big Brother Watch, which also raised concerns about Google’s privacy changes last year, welcomed the formal investigation.
“The company has ignored the authorities and refused to make any meaningful changes to how it collects and uses people's data.
“Consumers are increasingly concerned about how their data is being used and it is essential that those breaking the law are properly punished. It is essential regulators find a sanction that is not just a slap on the wrists and will make Google’s think twice before it ignores consumer rights again.”
Google today repeated its view that the new policy makes things simpler for consumers and denied breaking the law.