Brit Jamie McDonald running 6,000 miles across US 'doesn't know if he'll make it'

Jamie McDonald from Gloucester is halfway through his huge solo run - the distance of 230 marathons - to raise money for children's hospitals.The 32-year-old has faced a number of ordeals on the route, including plantar fasciitis in his foot and an encounter with a mountain lion.Speaking from Austin, Texas, Mr McDonald revealed his motivation to carry on.