Google is to reduce the length of time it keeps personally identified data gathered from web users, after concerns were raised about the search giant’s privacy policies.

Previously, Google retained search queries and identifying information, such as Internet Protocol (IP) addresses, for as long as it thought useful.

In March, it announced a new policy to keep its server log data but make the information more anonymous so it cannot be linked to individual users after 18 to 24 months.

But this decision prompted concerns from the Article 29 Working Party, an independent European advisory body on data protection and privacy, that it did not comply with European law.

However, Google’s global privacy counsel Peter Fleischer says the company will now reduce the time it stores individual data to 18 months rather than 24.

In a letter to the Working Party he says any regulatory requirement to keep data for less than 18 months would undermine Google’s services.

‘After considering the Working Party's concerns, we are announcing a new policy: to anonymise our search server logs after 18 months, rather than the previously established period of 18 to 24 months,’ he said.

‘We believe that we can still address our legitimate interests in security, innovation and anti-fraud efforts with this shorter period.’

Google says retaining search server logs is vital to improving search algorithms for the benefit of users, to defend systems from hacking, fight spam, and to respond to valid legal orders to comply with data retention obligations.

Fleischer says it is difficult to operate a global internet business according to different national standards. The US Department of Justice recently called for a 24 month data retention period.