Several of the UK's most popular brands have today been accused of contributing to the destruction of the Indonesian rainforest through their purchase of palm oil from suppliers engaged in the illegal destruction of forests and peat lands.

A Greenpeace investigation, entitled Cooking the Climate, has revealed that companies including Nestle, Unilever and Procter & Gamble (P&G) are linked to the destruction of Indonesia's forests and peat lands through their purchasing of palm oil.

Research conducted in Indonesia revealed that at least one major palm oil producer, Duta Palma, is "engaged in illegal activities, including the large-scale clearance and destruction of deep peat lands protected under Indonesian law".

Andy Tait, campaigns manager at Greenpeace, said there was evidence that Duta Palma was converting eight-metre-deep peat lands into plantations, in contravention of Indonesian law protecting all peat lands of a depth greater than two metres.

The report said that the peat lands represent a massive carbon store, and that the widespread clearing, draining and burning of Indonesian peat land swamp forests to make way for palm oil plantations now accounts for four per cent of the world's annual greenhouse gas emissions. It added that with the UN predicting demand for palm oil will double by 2030, driven largely by demand for the crop as a biofuel, there is an urgent need for a global moratorium on converting Indonesia's peat forest into further plantations.

Both Nestle and P&G said that they followed sustainability guidelines when sourcing products and were working closely with the palm oil industry group the Roundtable on Sustainable Palm Oil (RSPO) to develop stringent environmental best practice standards for the sector.

A spokeswoman for Nestle said that the RSPO is currently working on developing sustainability guidelines, and that "approximately 95 per cent of the palm oil and palm-kernel oil used by Nestlé comes from suppliers who are members of the RSPO".

The RSPO is due to meet this month to finalise a set criteria that would commit its members to a number of best practices, including compliance with all local laws, sustainable agricultural methods and ethical employment policies.

However, Tait argued that the RSPO was currently being used as a "green fig leaf" to cover up the unsustainable practices of some of its members, pointing out that Duta Palma, the company found to be undertaking illegal forest clearing, was a member of the group.

Tait also argued that a lack of segregation in the global market between palm oil grown on sustainable plantations and that grown on land converted from peat swamps meant there was no way for customers to be sure where the product had originated.

"We need a moratorium on the conversion of these peat lands, and companies have a critical role to play in that by stopping trading with any company found to be engaging in forest conversion," Tait said. "There is a precedent in that there has been a similar problem in the Amazon with Soya plantations and group of forward-looking European companies have helped make a major difference by enforcing a moratorium on the practice."