This shocking footage shows the jaw-dropping moment a cliff jumper "nearly died" after back-flipping from the top of Britain's most powerful waterfall. Matty Harper, 25, flung himself 70 ft from top of the waterfall into its turbulent waters and forced him underwater and left gasping for breath. After almost eight seconds, daredevil Matty, who says he's "lucky to be alive" surfaced to the relief of on-lookers. However he has warned others from undertaking the leap. He carried out the death-defying stunt at High Force waterfall in Teesdale, County Durham, on Sunday (14), as shocked visitors watched on and videoed.