David was rehearsing the Jerk Back - one of the most dangerous stunts in the business - at Leavesden studios near Watford, Herts, six weeks ago.

• 那位朋友说：“那天的早些时候大卫已经做过这个特技动作，干过他说那比平时更难表演，而且说他在被向后拉拽时觉得很痛。”