The firm issued its half-year results for the period ended 30 June, which saw pre-tax profits down 18% on the same period last year.

Sales increased slightly to 189m, with exceptional charges reported of 2.2m for the period.

Chairman Cameron McLatchie said in view of the continuing difficult market conditions, profits for the full year would be significantly below that of last year.

"Anticipated increases in raw material prices will now clearly impact on the company's performance for the full year," he said.