Raval, Trevor Rees-Jones was indeed wearing a seat belt. In fact, he was the only occupant of the vehicle who buckled up. The doctors all agree that this is the one factor that saved his life. Even with the seatbelt fastened his injuries were traumatic.
There was some controversy around the fact that he might not have ensured that the Princess of Wales, whose safety was his responsibility- did not buckle her seat belt.
Who is to say that the famously willful Diana did not do as she was asked?
Rees-Jones has little to no memory of the tragedy.