Manufacturers including Nestle and Mars, as well as retailers like Sainsbury’s and Marks and Spencer, have pledged to further cut food waste and carbon emissions in the UK.

Forty-five food and drink manufacturers and retailers, including all major grocers, have signed up to the third phase of The Courtauld Commitment, first launched in 2005 to reduce waste.

The new round of pledges include targets to cut 1.1m tonnes of waste from the supply chain and households, as well as a reduction of 2.9m tonnes of CO2.

The commitments equate to a 5% cut in household food and drink waste by 2015 from 2012 levels, a 3% fall in “traditional grocery ingredient, product and packaging waste” from the supply chain and a 3% reduction in carbon through “improved packaging design”.

The Courtauld Commitment has so far had broad success, although of the targets set under phase one of the voluntary agreement – which ran from 2005 to 2010 – one, which looked at the total amount of packaging used by companies, was missed. The full results from the second phase will be reported later this year.

Fewer companies have so far signed up to the third phase than the second round of the commitment, which involved 53 companies. A spokesperson for the Waste & Resources Action Programme, the government-backed body that implements the commitment, said more firms were set to sign up to the new pledges but were waiting on “paperwork”. Other previous signatories, she said, were going through restructuring changes and would agree to the new pledges in time.

Dr Liz Goodwin, CEO of WRAP, said the third stage of the Courtauld Commitment, “builds on the achievements” of the first two phases. She added: “Over the course of the three phases of the agreement, a 20% reduction in UK household food waste is achievable, a deeply impressive outcome.”

The British Retail Consortium, which represents major UK grocers, said the third phase of the commitment would add to the “excellent progress” made on cutting food waste.

Andrew Opie, food and sustainability director at the BRC, said: “These new targets build on the major strides already made by grocery retailers to reduce food and packaging waste.  Despite the downturn and other challenges affecting business, the retail industry is continuing to innovate and collaborate on waste reduction as well as working hard to meet wider green goals across all aspects of its operations. That’s delivering real environmental benefits as well as value for customers.”

The UK’s Food and Drink Federation, the industry association for manufacturers, echoed the BRC’s assessment that “significant progress” had been made under the first two phases of The Courtauld Commitment.

Andrew Kuyk, the FDF’s director of sustainability, said it was “imperative” food and drink businesses “address resource efficiency” within their operations and across the supply chain, given the challenges of food security and climate change.