Ayman al-Zawahri's 20 minute speech was entitled "Hateful Britain and its Indian Slaves," CBS News reports.
It was produced by as-Sahab, the multimedia wing of al Qaeda, to be distributed to extremist Web sites, said the U.S.-based SITE, which monitors al Qaeda messages.
The authenticity of the tape, also reported by Alexandria, Va.-based IntelCenter, could not be independently confirmed.
Osama 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 an insult to Islam.
Al-Zawahri said that a "firm response" is in preparation to retaliate against this offense, CBS News reports.
Addressing British Prime Minister Gordon Brown, the al Qaeda deputy chief said Britain's strategy in the Middle East "has brought catastrophes and defeats in Afghanistan and Iraq and even in the center of London," reports CBS News.
"If you haven't learned your lesson yet," al-Zawahri continued, "we are ready to repeat it again until we are sure you have fully understood," CBS News reports.
Hung Jury In July 21, 2005 Plot Case
A jury that convicted four men of plotting to bomb London's public transport system on July 21, 2005, was dismissed Tuesday after failing to reach a verdict against two other defendants.
Authorities believe the failed attacks on three subway trains and a double-decker bus were a deliberate echo of the suicide bombings that killed 52 passengers on the network two weeks earlier.
TheMuktar Said Ibrahim, 29; Yassin Omar, 26; Ramzi Mohammed, 25; and Hussain Osman, 28, guilty of conspiracy to murder. They face sentencing on Wednesday.
Fulford gave prosecutors until Wednesday morning to say whether they would seek a retrial of Asiedu and Yahya.
All six defendants denied the charges, saying the devices were duds and their actions a protest against the Iraq war. But police and prosecutors said scientific tests proved the bombs were all viable. They do not know why they did not work.
During the six-month trial, prosecutors say Asiedu lost his nerve and abandoned his device in a London park. Yahya left Britain for Ethiopia several weeks before the attacks.
During the trial, Asiedu turned on the others and claimed Ibrahim, the gang's self-proclaimed leader, had wanted the attacks "to be bigger and better" than the July 7 bombs.
The four attempted to detonate explosives-laden backpacks on three subway trains and a bus, as in the July 7, 2005, attacks. The devices — made from a volatile mix of hydrogen peroxide and flour — failed to explode, and no one was injured.
The explosives were packed in plastic tubs, with screws, bolts and other pieces of metal taped to the outside as shrapnel. The detonators contained triacetone triperoxide (TATP), an explosive used by the July 7 bombers.
Omar and Mohammed set off their devices aboard two subway trains; a couple of hours later Ibrahim's device failed aboard a double-decker bus.
Unlike three of the four July 7 bombers, who were British-born, those in the July 21 plot had come to Britain as young men from places like Eritrea, Ethiopia and Somalia. Some had become British citizens, while others had refugee status.
London, Glasgow Investigation Update
A suspect in the failed terror attack on Scotland's busiest airport was unlikely to survive his severe burn injuries, a doctor who treated him said Tuesday.
"The prognosis is not good and he is not likely to survive," a member of the medical team that treated him at the Royal Alexandra Hospital near Glasgow said on condition of anonymity because details about patients' condition are not to be made public. "He has third-degree burns over most of his torso and limbs. It is beyond repair and because he has lost so much skin he is now vulnerable to infection and won't be able to fight it."
Earlier Tuesday, it emerged that Ahmed had once worked as an aeronautical engineer, as an Australian investigator traveled to India to expand the British terror inquiry.
Ahmed worked in Bangalore as an aeronautical engineer for Infotech Enterprises, a large outsourcing firm, from December 2005 to August 2006, said company spokesman K.S. Susindar.
Infotech works with some of the biggest companies in aviation, including Boeing and Airbus, among others — possibly giving Ahmed access to sensitive design information from the companies.
Susindar declined to comment on whether Ahmed had access to design secrets or what projects he worked on.
"He was a sincere employee and from what I can gather he gave no problems whatsoever," said Susindar.
The services Infotech offered its clients was not immediately clear, but most of the aviation work outsourced to Indian companies includes software support for cabin lighting, display of information in the cockpit, in-flight entertainment and communication.
In some cases, it could involve designing software for flight control systems, navigation and surveillance.
Ajay Prasad, India's former civil aviation secretary, doubted Ahmed worked on any sensitive projects.
Not much aircraft design work "was outsourced by these companies, so I don't think there is any major (danger)," said Prasad. "Unless one has an idea of what kind of work this company was doing for Boeing or Airbus, it's very difficult to say."
Sabeel Ahmed, 26, Kafeel's brother, is being held in Liverpool as a suspect in the terror plot. Sabeel, who worked as a doctor, and Kafeel are among eight people held in the case.
A third Indian, Mohammad Haneef, is being held in Australia for questioning.