PepsiCo has pledged to make substantial improvements to the sustainability of its potato sourcing by cutting the carbon emissions and water use of core UK crops by 50% in the next five years.

In its first report on sustainable farming, the Walkers crisp maker said it planned to swap to more environmentally efficient varieties by 2015 in a bid to cut waste and boost yield.

It would also introduce a monitoring system called iCrop to enable its farmers to better manage their ­water use and carbon ­emissions.