San Francisco ? Google Inc.’s privacy practices are the worst among the Internet’s top destinations, according to a watchdog group seeking to intensify the recent focus on how the online search leader handles personal information about its users.

In a report released Saturday, London-based Privacy International assigned Google its lowest possible grade. The category is reserved for companies with “comprehensive consumer surveillance and entrenched hostility to privacy.”

None of the 22 other surveyed companies – a group that included Yahoo Inc., Microsoft Corp. and AOL – sunk to that level, according to Privacy International.

While a number of other Internet companies have troubling policies, none comes as close to Google to “achieving status as an endemic threat to privacy,” Privacy International said in an explanation of its findings.

In a statement from one of its lawyers, Google said it aggressively protects its users’ privacy and stands behind its track record. In its most conspicuous defense of user privacy, Google last year successfully fought a U.S. Justice Department subpoena demanding to review millions of search requests.

The company says it stockpiles data to help its search engine better understand its users so it can deliver more relevant results and advertisements.

Privacy International is particularly troubled by Google’s ability to match data gathered by its search engine with information collected from other services such as e-mail, instant messaging and maps.