The swoop followed a tip-off from a member of the public.

Officers executed a warrant on Thursday afternoon, searching staff lockers and offices.

A 40-year-old male employee from Bottesford and a 36-year-old man from Scunthorpe were arrested at the plant.

Company policy

They were questioned overnight in Scunthorpe before being released on police bail pending further inquiries.

A spokeswoman for Corus said the company has a clear policy about drugs and alcohol.

"Where an employee has a drug or alcohol problem and comes to us, Corus will provide comprehensive support," she explained.

"Where an employee has a drug or alcohol problem and attends work under the influence without having alerted us to the problem, this would be treated as gross misconduct."