One of the 21 July bomb suspects has admitted lying to police during interviews after he was arrested.
Muktar Ibrahim denies the devices could have hurt anyone
Muktar Ibrahim told Woolwich Crown Court that he and co-defendant Ramzi Mohammed had invented a false story to tell officers.
And he admitted lying about not knowing some of the other men involved in the alleged plot.
Six men deny conspiracy to murder and to cause explosions across London's transport network on 21 July 2005.
Mr Ibrahim, 29, has previously admitted making the homemade devices found by police, but he insisted none of them were capable of injuring anyone.
He initially told the jury that he and Mr Mohammed did not discuss what they would say if they were arrested.
But later under cross-examination he said he had "just remembered" that they had talked about it.
He said they had agreed to say he only turned up at Mr Mohammed's flat in North Kensington, west London, two days before they were both arrested.
The jury had heard earlier he was at the property eight days before the arrests.
Nigel Sweeney QC, prosecuting, said Mr Ibrahim had lied about knowing Mr Mohammed, Hussain Osman and Manfo Asiedu since 2004.
Mr Ibrahim, the alleged bus bomber, told the court he had only trying to protect them.
"The arrest was serious so I didn't want to incriminate anybody," he said.
"I just thought the best thing is just to speak for myself and it's not the right thing, I admit that."
Mr Sweeney also asked Mr Ibrahim why he had not told the police the alleged plot was a hoax, as he now claimed.
The barrister said: "You held the key of being able to say, 'Look, don't worry, there's no one else out there, I know that because it's my plan. All the materials have been got rid of, there's nothing left, there's no one left, it's the end.'"
Mr Ibrahim said he had kept quiet because he didn't trust the police.
"Looking back I should have said it was a hoax, but there's nothing I can do now."
Mr Sweeney asked him: "It couldn't be, could it, that when you did speak with the police you didn't mention it because you hadn't thought of it at that point?"
The defendant denied that was the case.
Mr Ibrahim, of Stoke Newington, north London, is accused along with Mr Mohammed, 25,; Mr Omar, 26, of New Southgate, north London; Mr Asiedu, 33, and Mr Osman 28, both of no fixed address; and Adel Yahya, 24, of Tottenham, north London.
The trial continues.