A videotape claiming Osama Bin Laden is still "alive and fighting" dates back to September, Arab television channel al-Jazeera has admitted.
The video did not feature Bin Laden himself
Al-Jazeera's editor-in-chief, Ahmed Sheikh, said his channel had broadcast the footage by mistake.
Mr Sheikh said it had received the video in September and aired "the important parts" at the time.
In the video, Bin Laden's deputy, Ayman al-Zawahiri, also claimed al-Qaeda was behind the London bombings on 7 July.
"We got the videotape in September, and back then we aired what we thought were the important parts," Mr Sheikh told the AFP news agency.
"There was a misunderstanding today, and we aired these extracts today by mistake."
'Message of joy'
Zawahiri claimed in September that al-Qaeda's leader was still alive and leading a "holy war" against the West.
He called for attacks on oil targets and said al-Qaeda was "spreading and expanding and strengthening".
News of Bin Laden's good health was a "message of joy to all Muslims", Mr Zawahri said.
Al-Qaeda, he said, was a "popular organisation confronting a new Crusader Zionist Western and Israeli campaign, in defence of all violated Muslim lands".