India-born Dhiren Barot, who allegedly plotted to bomb key installations in the United Kingdom and the United States, was sentenced to life imprisonment by the Woolwich Crown Court on Tuesday. He will serve at least 40 years in prison.
Barot, 34, admitted his role in the conspiracy. Prosecutor Edmond Lawson QC told the court that Barot had planned to unleash a "memorable black day" of terror.
He said evidence suggested "the conspiracy was probably in its final stages". Barot's defence team rejected the claim.
Barot was born to Hindu parents in Gujarat. The family later migrated to the UK. Barot embraced Islam when he was 20.
Prosecutors described Barot as "a member or close associate" of the Al-Qaeda. He was arrested by the police in August 2004.
Barot intended to manufacture and deploy improvised explosive devices that used gas cylinders hidden in limousines as trigger. His targets included several hotels like Savoy and an underground train passing under the Thames.
Barot also planned to strike at the IMF and the World Bank in Washington DC, the New York Stock Exchange building, the Citigroup headquarters and the Prudential building in Newark, New Jersey.
Barot's plans were found on a laptop computer seized during a raid on a house in Gujarat, Pakistan, in July 2004. Lawson told the court significant work was carried out to establish Barot's authorship of the 39-page document.
In the document, Barot says his primary objective was to "inflict mass damage and chaos".