In what is described as the biggest terror trial in the UK, the five Muslim men were found guilty of planning to use 600 kg of ammonium nitrate fertiliser to make bombs for an al-Qaeda-inspired campaign of revenge for Britain's support to the United States on its 'war on terror'.
The judge, Sir Michael Astill, told Omar Khyam, 25, the plot ringleader, he would have to serve a minimum of 20 years in jail. He warned all five that they might spend the rest of their lives in prison.
"You have betrayed this country that has given you every opportunity," he said. "All of you may never be released. It is not a foregone conclusion."
Khyam, from Crawley, West Sussex, was found guilty of conspiring to cause explosions likely to endanger life between January1, 2003 and March 31, 2004, possessing 600 kg of ammonium nitrate fertiliser for terrorist purposes and possessing aluminum powder for terrorism.
Four other men were also found guilty on the first charge: Waheed Mahmood, 35, and Jawad Akbar, 23, also from Crawley, West Sussex, Anthony Garcia, 25, from Barkingside, east London; and Salahuddin Amin, 32, from Luton.
Garcia and Mahmood were sentenced to at least 20 years in prison; Akbar and Amin face a minimum of 17 and half years.
The terror cell was said to have schemed with Canadian Mohammed Momin Khawaja and American Mohammed Junaid Babar.
Relatives of Khan and his fellow plotters demanded to know why police did not act against Khan and Tanweer after they arrested Khyam and his six co-defendants in March 2004, a full 16 months before the July 7 blasts.
Khyam and Khan met at least four times in England while Khyam was under Mi5, British intelligence agency, surveillance and in the final stages of his plotting. On one occasion, agents even recorded the pair talking about terrorism.
However, police and intelligence officers regarded Khan and Tanweer as "peripheral" figures, and no action was taken against them even after Khyam and his fellow plotters were detained.
"The consequences of that level of incompetence were such that my son killed. That is truly appalling," said Graham Foulkes, who lost his 22-year-old son, David, on July 7, 2005.
Details of the links to the July 7 pair were outlined in January 2006, with the prosecution arguing that the information should be permitted as evidence. The judge, however, ruled that the men might not receive a fair trial if the connection were known.
Monday's verdict came 10 days after Sir Michael said he would accept a majority decision from the jury, which had by that stage been deliberating for 21 days. The 12-month trial was the longest in UK terrorism history.
The seven men were arrested after the discovery of more than half a ton of chemical fertiliser in storage in west London.
According to police, Khyam wanted a series of bombs to go off at the same time or one after another on the same day, potentially killing hundreds of people.