Google's chief executive Larry Page has said rival Facebook is doing "a really bad job on their products," as his company announced the development of massive new UK headquarters in London.
Mr Page gave a wide-ranging interview to Wired magazine, which was conducted before Facebook launched its new Graph Search tool.
Asked whether competition from Facebook had motivated Google's social products, he said: "It’s not the way I think about it. We had real issues with how our users shared information, how they expressed their identity, and so on."
"And yeah, they're a company that's strong in that space. But they're also doing a really bad job on their products."
Mr Page said he was happy with the progress made by Google+.
"For us to succeed, is it necessary for some other company to fail? No. We're actually doing something different. I think it's outrageous to say that there's only space for one company in these areas."
Meanwhile, Google has bought a huge plot of land in King's Cross for a new UK office complex that could be worth £1B when completed.
The tech giant plans to build a 1-million-square-foot office and has purchased a 2.4-acre plot at the Kings Cross Central development, the property developers behind the project said.
Construction on the site is expected to start late this year and be completed in 2016, when Google would leave its current offices in Victoria and Holborn districts.
The new building will range in height from 7 to 11 stories.
The price of the purchase was not disclosed.
The Reuters news agency quoted sources as saying Google was investing £650m to buy and develop the site and that, once finished, the office building would be worth up to £1bn.
"This is a big investment by Google, we're committing further to the UK," Google's Vice President for Northern and Central Europe, Matt Brittin, said in a statement.
"It's good news for Google, for London and for the UK."
In the past two years Google has bought premises in Paris and Dublin.