Grangemouth oil refinery was one of several possible targets for a gang accused of plotting to blow up at least seven passenger jets in mid-air, a court heard yesterday.

A memory stick discovered in the home of one of the eight men on trial in Woolwich Crown Court in London contained detailed research about UK oil refineries and terminals, including Grangemouth in Stirlingshire. The prosecution alleged that the information, which was found in Assad Sarwar's house, could refer to other possible targets for the gang.

Mr Sarwar and seven other men deny conspiring to murder thousands of people by exploding homemade liquid bombs disguised as drinks on aircraft.

Meanwhile, Kingston Crown Court in London heard that three friends of the July 7 suicide bombers helped them to locate potential targets in the capital.

The London Eye, the London Aquarium and the Natural History Museum were among attractions where Waheed Ali, Sadeer Saleem and Mohammed Shakil are alleged to have undertaken a "hostile reconnaissance", jurors heard.

The three men were not behind the attacks, which killed 52 people and injured almost 200 others, but shared the "objectives" and two of them accompanied the 7/7 ringleader Mohammad Sidique Khan to Pakistan, the court heard.

Mr Ali, 24; Mr Saleem, 27; and Mr Shakil, 31, are accused of helping Khan, Shehzad Tanweer, Jermain Lindsay and Hasib Hussain, in what prosecutors say was a reconnaissance mission for the attacks.

Mr Ali, from east London, and Mr Saleem and Mr Shakil, who are both from Leeds, deny conspiring with the four suicide bombers to cause explosions between November 17, 2004, and July 8, 2005.