Five men have denied charges at the Old Bailey over the alleged London bombing attempts on 21 July last year.
Devices failed to explode on a bus and on Tube trains on 21 July
Ibrahim Muktar Said, 27, Ramzi Mohamed, 23, Yassin Omar, 24, and Hussain Osman, 27, all from London, denied conspiracy to murder and to cause explosions.
They also denied attempted murder of transport users and having improvised explosives with intent to endanger life. The trial is due in October.
Manfo Asiedu, 32, was not charged with attempted murder and denied the rest.
A sixth man, Adel Yahya, 23, from London, was charged with conspiracy to cause explosions likely to endanger life but did not enter a plea.
He was remanded to another hearing in June.
The attempted murder charges faced by Mr Mohamed, Mr Omar and Mr Osman relate to alleged failed bombings on London Tube trains.
The attempted murder charge faced by Mr Said relates to another alleged bombing attempt on a London bus.
Mr Asiedu is charged in connection with a device found in Little Wormwood Scrubs park in west London on 23 July.
A separate hearing remanded six further defendants to a June hearing on charges of assisting an offender, Mr Osman, and failing to disclose information on terrorism.
Mr Osman's wife, Yeshiemebet Girma, 29, her sister Mulumebet Girma, 21, their brother Asias Girma, 20, all of London, Shadi Sami Abdel Gadir, 23, and Omar Nagmeloin Almagboul, 20, of Brighton, and Mohamed Kabashi, 23, of no fixed abode, are due to face trial on 5 February next year.
Yeshiemebet Girma and Mr Kabashi appeared by video link, while the other defendants were on bail.
Five other people are due to face charges of assisting the alleged conspirators and failing to disclose information.