The ringleader of London's 2005 suicide bombers recorded a video for his daughter when he left for Pakistan on a previous mission expecting to die, a prosecutor said on Thursday.

The video, never previously shown in public, was played at the trial of three men accused of undertaking reconnaissance for the July 7 attacks on London transport which killed 52 people.

Mohammad Sidique Khan, leader of the four suicide bombers, recorded the video to say goodbye to his baby daughter Maryam before he left on a visit to Pakistan in November 2004.

Prosecutor Neil Flewitt told Kingston Crown Court in southwest London that Khan recorded the video because he was preparing to die while fighting jihad in Afghanistan. But he later changed his mind and used the visit to start planning for the London attacks, Flewitt said.

"Sweetheart, not long to go now. And I'm going to really, really miss you a lot," Khan says into the camera while he holds his daughter.

"I'm doing what I am doing for the sake of Islam, not, you know, it's not for materialistic or worldly benefits."

Flewitt said it was clear from the video that Khan did not expect to see his daughter again.

"Put bluntly, he knew that he was going to his death and he went voluntarily then, as he went willingly when he blew himself up on the July 7, 2005," he added.

Khan also introduces his daughter's "uncles" - two of the bombers, Shehzad Tanweer, Hasib Hussain, and Waheed Ali, one of the three men accused of scouting for the attacks.

The video was found by Khan's wife, who gave it to a friend who later passed it on to police after the July 7 bombings, the court heard.

Khan appeared in a previous video aired on Al Jazeera in September 2005. In that recording, he invoked Osama bin Laden and warned of more attacks unless "atrocities" against Muslims stopped.

"Until we feel secure you will be our targets. Until you stop the bombing, gassing, imprisonment and torture ... we will not stop this fight. We are at war and I am a soldier," he said in the earlier video.