Google has accused Microsoft of "cheating" by copying its search engine results and regurgitating them on its rival product, Bing.

The companies engaged in chatty exchanges yesterday , with employees sniping at one another on blogs and via Twitter.

Amit Singhal, a senior software engineer at Google, posted an official blog explaining how his team had caught Microsoft out by deliberately posting rogue results which later appeared on Bing. In one case, Google made the nonsensical term "delhipublicschool40 chdjob" return a completely unrelated suggestion for the website of a credit union in Ohio, only for the same result to soon begin appearing on Bing.

Bing's vice-president, Harry Shum, shot back, saying the method involved was one of hundreds it used to produce results.

Jon Crowcroft, a professor of communication systems at Cambridge University who sits on Microsoft's advisory board, said: "I don't think Google are genuinely surprised. I think it's a shot across the bows of Microsoft."