Titterington said Google sets out the conditions under which it is obliged to share information with governments, but it does not say what the limits of this sharing is.
The warnings follow calls from data protection group Article 29 for Google to explain why it holds the data it does and for the time it does.
A Google spokesman said it takes internal reviews of its data collection storage and processing practices and restrict access to personal information to Google employees, contractors and agents who need to develop its services. "These individuals are bound by confidentiality obligations and may be subject criminal prosecution if they fail to meet these obligations."
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