Street View comprises 360 degree photographs of a town's streets, and is already live in the US and some European countries. It was launched today in the UK with coverage of 25 towns and cities.
People can be seen and sometimes identified in the photos as they originally appeared, but Google has implemented automatic image blurring technology for faces and car number plates.
Privacy watchdog the Information Commissioner's Office (ICO) has given the service the all-clear, saying that the blurring means that the service does not publish personal information and so does not break the law.
Davies told OUT-LAW.COM that he will mount a legal challenge to the ICO's opinion.
"There still hasn't been a formal complaint put to the Information Commissioner, but we will [file one] now on the basis of prior consent being needed for this service," said Davies. "I think there is something of a test case in this. We are arguing that a line has to be drawn to empower the individual to make a conscious decision whether to allow his or her images on to such a system."
The UK's privacy watchdog the Information Commissioner's Office (ICO) endorsed the service last summer.
"We are satisfied that Google is putting in place adequate safeguards to avoid any risk to the privacy or safety of individuals, including the blurring of vehicle registration marks and the faces of anyone included in Street View images," said an ICO statement.
Google also said that people who did not want their photo to appear on the service could complain and have it taken down.
"Although it is possible that in certain limited circumstances an image may allow the identification of an individual, it is clear that Google are keen to capture images of streets and not individuals," said the ICO last summer. "Further there is an easy mechanism by which individuals can report an image that causes them concern to Google and request that it is removed."
Davies said that he is not sure what exactly the legal basis of a challenge to the system or to the ICO's opinion would be, but said that it was an established legal principle that a person's consent is required for a photograph that is used commercially.
"There have been highly successful cases in the courts regarding celebrities who have not given consent for the commercial use of their images. That may or may not fall within the Data Protection Act. In any event we think there is enough case law for this to proceed, to form a basis for a challenge," he said.
Technology lawyer Struan Robertson of Pinsent Masons, the law firm behind OUT-LAW.COM, said that Davies's assessment of the law is flawed.
"There is no general legal requirement that people's permission should be obtained before a photo of them is taken in a public place, even if the purpose is a commercial one," said Robertson.
"People will have rights if the photos are deemed to be personal data, and collecting images in a way that complies with the Data Protection Act was a legal challenge for Google," said Robertson.
"The Act says that people should be notified about their pictures being taken before that happens, though consent is not required. Short of using loudspeakers on cars, it was impossible for Google to notify people that their pictures were being taken. But the company's safeguards, in particular the blurring of faces and number plates, have been approved by the Information Commissioner, a blessing that is extremely important."
Robertson said that if circumstances arise in which people suffer as a consequence of Street View, they can take specific action under the Data Protection Act.
"There will be some cases where people are identifiable on Google Street View because the blurring technology missed them or because they can be recognised despite the blurring," he said. "These individuals can complain to Google if they're upset by the posting of their image and they can have the photos removed. If they've suffered damage and distress as a consequence of the photographs, the Data Protection Act gives them a right to sue, and Google knows that."
Individuals have won cases in court by arguing that photographs of them breached their human right of privacy, rather than their rights under the Data Protection Act, but Robertson said that these rulings do not support Davies' argument.
"In Street View images, the inclusion of people is incidental – they just happen to be on the street," he said. "That is not the case in any of the privacy rulings, where the person bringing the claim was the focus of the photo."
Photographs of author JK Rowlings's infant son, David Murray, led to a ruling last year in the Court of Appeal.
"If the photographs had been taken…to show the scene in a street by a passer-by and later published as street scenes, that would be one thing, but they were not taken as street scenes but were taken deliberately, in secret and with a view to their subsequent publication," wrote Sir Anthony Clarke. "They were taken for the purpose of publication for profit, no doubt in the knowledge that the parents would have objected to them."
Sir Anthony also said that famous people have less of an expectation of privacy than those that do not seek the spotlight. "David may have a reasonable expectation of privacy in circumstances in which his famous mother might not," he wrote.
Robertson said that he doubts Davies' challenge will succeed.
"There are safeguards and remedies available, so while Street View might make some people uncomfortable, I can't see any legal grounds for stopping it," he said.