A six to seven metre portion came off the blade in the incident in Lem, Western Jutland, a Vestas spokesman says. He adds that the company is investigating the cause of the incident.

“We don’t see this as a design fault,” he says. “This is a prototype, so it is meant to be tested and bent and broken.” But Vestas shares fell on the Copenhagen stock market as the news emerged.

Vestas recently won an order for the V112 for the 420 MW Macarthur wind farm, the largest wind project in Australia and the turbine is also due to be delivered to Portuguese wind power giant EDPR as part of the massive framework agreement signed earlier this year.

“This