The July 21 bombers were planning a co-ordinated attack designed to cause death and destruction on London's transport system, the Crown Prosecution Service said.
In a statement, Susan Hemming, Head of the CPS Counter Terrorism Division, said: "Over many months they designed and built their own bombs.
"They could have been in no doubt as to the consequences of their actions. While the implementation of their plan was incompetent, their aim was clear. They wanted to kill and maim on a massive scale."
Ms Hemming added: "Exactly two weeks after the terrorist attacks on 7/7 these men targeted the same transport system and tried to cause the same level of death and destruction.
"They knew what would happen; they had seen the devastation produced by 7/7 and the fact that they continued with their plan shows their brutal intent.
"The Crown Prosecution Service has informed the court that we intend to seek a retrial for conspiracy to murder against Adel Yahya and Manfo Kwaku Asiedu and would remind the media that these two men are only accused of these offences and have the right to a fair trial."
Director of Public Prosecutions Sir Ken Macdonald QC said prosecution evidence in the trial had been released to the media to "demystify" the legal process and give "all the communities of Britain confidence in this prosecution".
He said: "Following on so soon after 7/7, this case aroused massive public interest. We arranged with the police and the court for prosecution material to be made available to the media on a day-by-day basis.
"This opened up the Criminal Justice System, demystifying it and showing the public the evidence upon which the jury based their decision. Our purpose was to give all the communities of Britain confidence in this prosecution.
"We wanted the public to see for themselves the dreadful acts planned against people in London."
