Up to 50 people disembarked from the overcrowded bus blown up in the July 7 attacks just moments before the devastating explosion tore through it, the official inquest into the events has heard.

Unaware of what was disrupting the transport network that morning and forcing legions of would-be Tube passengers to travel overground, the driver had made a diversion.

Following protocol, he announced this to his passengers, advising those whose destinations were nearby that they might be better off walking.

Between 30 and 50 hopped off - unaware that their driver's advice may have saved their lives.

Forced to depart from his normal number 30 route by police blocking the road, Greek-born George Psaradakis did not now know where he was.

Giving evidence, he said: "Lots of people got off the bus... I pulled away slowly, at crawling speed. When I was near (two) traffic officers I opened my window and called them.

"I said to them 'what is the name of this place?'... They said Tavistock Square, so I thanked them and tried to call my garage and then - bang. The explosion."

At first he thought he had hit something in the road, but he soon realised the full horror of what had happened.

"The windscreen blew away, debris fell all over me," he said. "I was stunned, shocked. I touched my head and could only feel dust."

Confused as he was, he dragged himself from his seat and off the bus, stepping into a road strewn with body parts.

"I kept looking if there is anybody I could help but again people were dismembered and all dying."

Recalling the emotion he felt as he gazed at the remains of his passengers, who a few minutes earlier had been talking and laughing, he said: "I never felt that way ever in my life...

"Seeing my passengers in such a state really shocked me, I was overwhelmed."