The US Government is taking legal action to gain access to Google’s vast database of internet searches in an historic clash over privacy.

The Bush Administration has asked a federal judge to order the world’s most popular internet search engine to hand over the records of all Google searches for any one-week period, as well as other closely guarded data. The California-based company is to fight the move.

The immediate flashpoint is the Government’s effort to revive an online child pornography law that was struck down by the Supreme Court two years ago.

The US Justice Department requested access to Google’s search records as part of its effort to prove the constitutionality of the 1998 Child Online Protection Act.

The controversial law sought to curb minors’ access to internet pornography by making it a crime to publish material that is "harmful to minors" on the web.

The law was immediately challenged by civil liberties groups and never came into force. It was eventually struck down by the Supreme Court on the grounds that it was unconstitutionally restrictive of free speech.

But the Supreme Court gave the Government a second chance to prove that the law’s proposed criminal penalties would work better to protect children than internet filters or other methods.

The Government’s request for Google data came to light when Justice Department lawyers filed papers in federal court in San Jose, California, revealing that the internet search firm had failed to comply with a subpeona for records in the case.

The Government indicated that other unnamed search engines had already agreed to release the information, but not Google, which runs 46 per cent of all US web searches.

"The production of those materials would be of significant assistance to the government’s preparation of its defence of the constitutionality of this important statute," the government lawyers wrote.

Nicole Wong, Google’s associate general counsel, countered: "Google is not a party to this lawsuit, and the demand for the information is overreaching."

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