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The ICO has issued a formal statement on their web site, saying:
"It is Google’s responsibility to ensure all vehicle registration marks and faces are satisfactorily blurred. Individuals who feel that an image does identify them (and are unhappy with this) should contact Google direct to get the image removed. Individuals who have raised concerns with Google about their image being included - and who do not think they have received a satisfactory response - can complain to the ICO."
Furthermore, Google actually sought counselling from the ICO prior to launching Street View, and ICO had said that Google has done enough to protect the privacy of individuals.