In October 2010 the Environment Agency found the company guilty of falsifying records in order to avoid paying £1.2m to improve its treatment system.

Managing director Chris Rosser said: "We are delighted that the Court of Appeal has found in our favour. We take our environmental responsibilities very seriously and have always strongly refuted the allegations.

"As a company we are committed to ensuring that our environmental performance is continually improving and we look forward to maintaining a close working relationship with the Environment Agency."

At the time, the company’s technical manager Christopher Steer was found guilty of falsifying records relating to the amount of effluent that was discharged from its Higher Kings paper mill in Devon.

The case against St Regis, which is a subsidiary of DS Smith, as a company was adjourned to April 2011. However, the company was granted a leave of appeal in April.

In September this year St Regis sold the mill, which produces coloured card for offices, to Asia File Corporation.