A dinner-time chat with al-Qa'ida chief

Bin Laden tape: screening and translation

The Pentagon spent days painstakingly viewing the tape of Osama bin Laden to ensure it had the best possible translation of what is said in the almost hour-long play time before releasing it yesterday for public consumption.

Four translators were bought in by the defence department to provide a consistent translation that was eventually shown as a subtitled text beneath the video images. Another version, with an Arabic text, was also prepared and made available for broadcast in the Arab world.

It was thought that the tape shows an al-Qa'ida dinner held in a guest house in Kandahar, the former Taliban stronghold, on 9 November. It was reportedly found by CIA agents in a house in Jalalabad, in eastern Afghanistan. US officials have speculated that it was left in the house by mistake when al-Qa'ida operatives were forced to flee as American bombings escalated.

The delay in releasing the tape was partly to do with the poor quality of the sound. In some instances the subtitles revert simply to the message "inaudible". While the Pentagon was able to use the latest technology to enhance the soundtrack, some sections of the conversations were simply too garbled for the translators to understand.

The tape was also intensively screened by officials to ensure that it contained nothing that could compromise national security.

Some members of Congress who were given an earlier glimpse of the tape warned that it may have been left behind on purpose and that it could therefore contain some kind of coded message that Mr bin Laden hoped to get out to his followers. However, the White House yesterday said that it was confident that this was not the case.

Finally, there was concern that the tape should be released on a day when there was little other news to compete with it. Because they are convinced that the tape provides convincing proof of Mr bin Laden's leading role in the terror attacks of 11 September, American officials were determined that it should receive maximum coverage on news programmes around the world.