Les Moonves, chief executive of CBS, ruled out buying a large social networking or user generated video site on Wednesday, a week after his opposite number at sister company Viacom was fired for missing out on digital acquisition opportunities.

Mr Moonves said social networking was an important phenomenon and CBS had looked at Facebook and YouTube, “but we’re not going to buy them”.

CBS would continue to strike digital partnerships, however, because “we’re all searching for what’s going to work.”

He questioned the valuations that have been mooted for the two young companies, asking: “Is YouTube worth $1bn today? Maybe, but it’s a lot of money. Is Facebook worth hundreds of millions of dollars? We’re looking at all these things.”

In reference to Tom Freston’s removal as chief executive of Viacom, which was blamed in part on his failure to buy a social networking site to rival News Corporation’s MySpace, Mr Moonves added: “Do I wish I owned [MySpace?] Sure. Fortunately, it wasn’t something I was negotiating for at the time.”

His relationship with Sumner Redstone, the Viacom and CBS chairman who fired Mr Freston, was “terrific,” Mr Moonves said. “I keep my head down, I do my job.”

Speaking to journalists at the Broadcasting Press Guild in London, Mr Moonves said that bankers had approached CBS about bids for both ITV, the UK’s largest commercial broadcaster, and Endemol, the Dutch production company behind the Big Brother reality TV series.

Investment bankers “did bring round the Endemol book [but] it’s not something we’re interested in,” he said. His comments come as Telefónica, Endemol’s controlling shareholder, is planning to sell the group and a management team has begun informal preparations for a buyout.

CBS had examined ITV more than a year ago, Mr Moonves said, but “we haven’t looked at it that closely.”