For an hour on Saturday morning, Google’s search engine returned the message: “Warning! This site may harm your computer” for almost every website on the Internet after a human error introduced a glitch to its malware warning procedure.

A fault on a website lasting one hour is not normally newsworthy, but Google’s search engine is the paradigmatic example of a super-reliable web service, the benchmark against which all IT systems are now compared – usually unfavourably.

According to Google’s own blog, the error occurred due to the improper insertion of the ‘/’ character into a line of code when the search engine’s list of potentially harmful sites was being updated.

Although the glitch was spotted quickly, it took roughly forty minutes to work through the system.

Google’s reputation for infallibility is becoming increasingly questionable. In October 2008, a 24 hour outage affected some users of the company’s suite of online applications – including email – angered business customers.