ABC chief executive Mark Scott says illegal downloads are responsible for some of Channel Ten’s disappointing ratings this year.

In a speech about the challenges that high-speed broadband is creating for broadcasters, Mr Scott noted that Ten’s suite of normally high rating US comedies had flopped this year. "To showcase the new 2012 ratings year on Ten, they had had held them back until several months after they were first broadcast to considerable fanfare in the US. Television networks have always done this in Australia," Mr Scott said at the Institute of a Broadband Enabled Society in Melbourne.

"But this year, Channel 10 found the audiences it had been expecting weren't there – they'd been and gone, online. They were good shows, easily found and watched within hours of their initial US broadcast. And there is no doubt that with its traditional younger demographic profile, a network like Ten is more vulnerable to this than other networks, but we‘re all vulnerable."

"Foxtel experienced the same missing audience problem with delayed screenings of programs like the latest series of Mad Men and The Newsroom – programs that had generated considerable media buzz months ago.