Greenergy, which supplies a fifth of the UK's petrol and diesel, said it has started making motor fuels from food waste, after initially feeding its plant with pure cooking oil.

The company only uses food that can't be sold, because the products are mis-shapen, past their sell by date or overcooked. The best ingredients are pies, pasties and crisps for their high fat content but other foodstuffs range from taramasalata to oil from fried fish containing breadcrumbs.

Greenergy is in a partnership with Brocklesby, a specialist in recycling edible oils that would previously have gone to landfill or compost, are now being converted for biofuel and energy production.

The fuel giant invested £50m in the biodiesel production facility at Immingham on the east coast to process used cooking oils, which are more complicated to process than "new" oils such as rapeseed.

It uses more than 20m litres a month of used cooking oil supplied from a range of food producers. However, extracting oil from foodstuffs is a new process.