Data regulators in the UK served Google with an enforcement notice giving them 35 days to delete material that was captured by the vehicles that take pictures for street view. The data is a small amount of information that was captured on local Wi-Fi networks.
What occurred was that as the camera-laden vehicles drive around taking pictures for street view they need to know where the properties are located so they can be accurately represented on the maps. In order to accomplish this, Google uses software that accesses local Wi-Fi networks and gathers small amounts of information to get location data.
Back in 2010, it came to light that Google was doing this and it caused concern in both the UK and the US concerning privacy issues. Google, at the time, said that it destroyed all the data. Then last year, Google admitted that it found some discs that still contained the information. The case was re-opened, but investigators could not find any evidence that Google intended to collect any personal information.
Google has agreed to comply with the order and states that the data was never even examined. It's quite likely that any additional data that got captured serves no purpose to Google, but with all the recent concerns of privacy that have been fueled by the likes of the NSA's spying has everyone on edge as to how seriously these companies take privacy concerns and how closely they are following the letter of the law in various countries.