Heinz has slashed its ­carbon output by 17,000 tonnes across its UK factories over the past four years the equivalent of taking 6,000 cars off the road a year.

Energy use and carbon dioxide emissions have been cut at factories producing Heinz Baked Beanz, soups and pasta in Kendal, Cumbria and Kitt Green near Wigan.

More than 13% of annual energy costs had been slashed at Kitt Green alone in the past two years, Heinz said. The site is Europe's largest food factory, turning out more than one billion food cans a year and about six million a day 12% of Heinz's global output.

The reduction is the result of a collaboration with The Carbon Trust to understand energy use in Heinz's production lines. The review led Heinz to capture and recycle more waste heat from its bean production, improve the efficiency of its boilers and change the design of production line machines. It is also ­exploring opportunities to produce power from waste and use more renewable energy across its factories in a bid to cut greenhouse gas emissions by 20% on 2005 levels by 2015.

"The Carbon Trust has helped us take a more strategic approach to carbon ­reduction," said Heinz UK and Ireland president Dave Woodward.

"As well as seeing some impressive results in the UK, we are successfully applying what we've learned across our global operations."