"He was an innocent man and we must accept full responsibility for his death," he said.
I know very little about this particular case or who was or was not at fault, but I was struck by the emptiness of Mr. Stephenson's concept of responsibility. He is not proposing that the police officers who killed Mr. de Menezes be punished in any way—the coroner had instructed the jury that they were not permitted to return a verdict of unlawful killing. He is not proposing that he himself or anyone else in any sense responsible be punished in any way or owe recompense to anyone. He is merely "accepting full responsibility" on behalf of his organization for killing an innocent man.
I am reminded of my reaction at the time of the Waco tragedy when Janet Reno, then Attorney General, made a similar statement on her own behalf. If you accept personal responsibility for actions that led to a substantial number of people, including children, being burned to death while under attack by people whose actions you consider yourself responsible for, the very least you can do is to resign. Subsequent suicide may be appropriate but is not mandatory.
But of course what she actually meant, and what he actually meant, was something closer to "all right already, stop bugging me."