Doctors said Mr Reeve, 42, whose recent films include Remains of the Day and Village of the Damned, suffered a severe neck injury after landing on his head. Last night the actor was said to be suffering full paralysis and breathing only with the aid of an artificial respirator.
"Mr Reeve currently has no movement or spontaneous respiration. He may require surgery to stabilise the upper spine in the near future," Dr John Jane, of the University of Virginia Medical Center in Charlottesville, said last night. Mr Reeve was reported to be in a serious but stable condition.
According to a local newspaper report, Mr Reeve was attempting the third jump of a 15-jump cross-country course when his own horse, Eastern Express, threw him forward. He suffered fractures to two cervical vertebrae and damage to his spinal cord even though he had been wearing protective equipment.
Dr Jane said the long-term damage was not known.