Big rise in volunteers for medical trials

The number of patients taking part in clinical trials in England has trebled in five years.

Figures from the National Institute of Health Research (NIHR) show almost 638,000 patients volunteered last year.

The rise may surprise some, given the publicity associated with a drug trial at a private research unit at London's Northwick Park hospital in 2006.

That trial - of a potential new drug for arthritis - left six volunteers dangerously ill.

Fergus Walsh reports.