Group communications manager Peter Aubusson said the firm had initially anticipated a 9m energy cost rise, but due to rising oil charges and high energy prices, that figure was now expected to double.

"Obviously we are doing everything we can to mitigate the impact, but the fact remains that paper is an energy-intensive industry," said Aubusson.

Lower demand for box products and overcapacity in Europe for corrugated materials has also put pressure on prices and margins.

"We are looking at other energy-saving measures," said Aubusson, adding that the manufacturer had benefited from its combined heat and power plant at its Kemsley mill in Kent.

However he underlined that the firm did not intend to close plants or cut jobs.

The increase is expected to continue to affect results in paper and corrugated packaging, where 90% of the company's energy and fuel costs are incurred.

In July, DS Smith sold its office stationery business John Dickinson Stationery for an undisclosed sum to European office supplies producer Groupe Hamelin.

Story by Andy Scott