Prosecutor David Waters told a jury at London's Old Bailey criminal court that the seven men allegedly planned to carry out the attack or attacks between January 2003 and March 2004.
During raids in and around London on March 30, 2004 police arrested the seven men and seized 600 kilograms of fertilizers which could be used to make bombs.
"The interception came only when most of the necessary components were in place and all that remained before their plans achieved their ultimate goal was for the target or targets to be finally agreed," Mr Waters told the jury.
He alleged they plotted to make "a bomb or bombs which would be deployed at the very least to destroy a strategic plant within the United Kingdom, or more realistically to kill and injure citizens of the UK."
The accused are: Omar Khyam, 24, Waheed Mahmood, 34, Shujah Mahmood, 19, and Jawad Akbar, 22, all from Crawley, south of London; Anthony Garcia (also known as Rahman Adam), 23, of Ilford, east London; Nabeel Hussain, 20, of Horley, Surrey, and Salahuddin Amin, 31, from Luton, north of London.
Suspects deny charges
The seven deny conspiring with Canadian Mohammed Momin Khawaja and with unknown others to set off a bomb or bombs.
Khyam, Garcia and Hussain also deny a charge under the Terrorism Act 2000 of possessing an article for terrorism, 600 kilograms of ammonium nitrate fertiliser, between November 5, 2003, and March 31, 2004.
Brothers Khyam and Shuja Mahmood also deny having aluminium powder for terrorism between October 1, 2003 and March 31, 2004. Aluminum powder can also be used to make bombs.
Mr Waters said the explosion or explosions were to take place in the United Kingdom but much of the preparation was to take place in Pakistan and in Canada through the work of Mr Khawaja.
But he said the courts would also hear evidence from the United States from the Pakistani-born US citizen Mohammed Babar, who pleaded guilty in New York to various terrorist related offences.
He said Mr Babar will be giving evidence to the Old Bailey as someone who had contact with most of the defendants.
"He had since the first Gulf War held what he describes as 'Jihad' views, that is Muslims should unite and join Jihad to fight anyone who is against Muslims or Islam," Mr Waters said.