The first three men to be charged in connection with the July 7, 2005 London suicide bombings went on trial on Thursday, accused of scouting for potential terrorist targets.
Mohammed Shakil, 31, Sadeer Saleem, 27 and Waheed Ali, 24, were friends with the bombers and shared common beliefs, Kingston Crown Court was told.
The bombers, Mohammad Sidique Khan, Shehzad Tanweer, Jermaine Lindsay and Hasib Hussain killed 52 people in co-ordinated morning rush hour attacks on three underground trains and a bus.
During a reconnaissance weekend seven months before the bombings, two of the accused visited the London Eye, the Natural History Museum and the London Aquarium, prosecutors alleged.
They said various types of evidence would help explain the group's motivations including contacts with people convicted of terrorist activity; travelling to Pakistan and possessing radical ideological material.
The court heard the accused had extensive contact with the bombers, which had been uncovered through mobile records, fingerprints on documents, family videos and surveillance.
Prosecutors allege that between Nov. 17, 2004 and July 8, 2005, they "unlawfully and maliciously" conspired with the four bombers and others unknown to cause explosions likely to endanger life or cause serious harm and injury.
The group, all from Beeston, Leeds, deny the single charge under the Explosive Substances Act 1883.
Dressed casually in open necked shirts, they sat in the dock, arms crossed and listening passively.
Prosecutor Neil Flewitt told the jury the group had developed violent thoughts against their adopted country.
When they were arrested, police uncovered material including praise for the Sept. 11, 2001 U.S. attacks, letters revealing Jihad ambitions and Web sites supporting Osama bin Laden and al Qaeda. Two of the group, Shakil and Ali, also separately travelled to Pakistan with Khan, the court was told.
Flewitt said it was not the prosecution case they had been directly involved in the London bombings by either making or transporting the bombs.
"However," he told the jury, "it is the prosecution case that the defendants associated with and shared the beliefs and objectives of the London bombers and so were willing to assist them in one particular and important aspect of their preparation for the London bombings."
In December 2004 the group travelled to London where they conducted "hostile reconnaissance of potential targets" over two days that was part of the "sinister plot to cause explosions".
They had denied the trip was suspicious.
Instead they said it was to enable Ali to visit his sister in East London. Saleem and Shakil admitted they had visited the London Eye, the museum and the aquarium but only "for purely social reasons".
The group, Flewitt said, admitted they knew the bombers but maintained their friendship was innocent and that they did not know about the plans to bomb the capital.
The trial, before Mr Justice Peter Gross, continues.
