Top Gear presenter Richard Hammond has suffered a "significant brain injury" after crashing a jet-powered car at speeds of up to 300mph during filming.
Doctors at Leeds General Infirmary said they were "reasonably optimistic" the 36-year-old would make a good recovery.
The BBC, which is likely to face close scrutiny, has begun an inquiry. The police and the Health and Safety Executive (HSE) are also investigating.