Ayman al-Zawahiri's 20 minute speech was entitled "Malicious Britain and its Indian Slaves." It was produced by as-Sahab, the multimedia wing of Al Qaeda, to be distributed to extremist web sites, said the US-based SITE intelligence group, which monitors Al Qaeda messages.
The authenticity of the tape could not be independently confirmed.
Usama bin Laden's deputy lashed out at Britain for having awarded a knighthood to Rushdie last month, saying it was defying the Islamic world by granting the honor to the author of "The Satanic Verses," deemed to insult Islam.
A "very precise response" is in preparation to retaliate against this offense, al-Zawahiri was quoted as saying by SITE.
Addressing British Prime Minister Gordon Brown, the Al Qaeda deputy chief said Britain's strategy in the Middle East "has brought tragedy and defeat upon you, not only in Afghanistan and Iraq but also in the center of London."
"And if you did not understand, listen, we are ready to repeat it for you," al-Zawahiri was quoted as warning the British prime minister.