Several 'Bamboo' toilet roll brands have been found to contain only tiny amounts of the fast-growing plant, instead the paper was mostly made up of harder woods including eucalyptus and acacia.
Following the growth in popularity of alternative toilet roll materials such as Bamboo in recent years, researchers at Which? tested samples from five top brands that claimed to be made only of bamboo, which is seen as more sustainable than wood as it is fast-growing and needs much less water and virtually no pesticide.
The loo paper trail found three of the samples - from Bumboo, Naked Sprout and Bazoo - contained barely any bamboo or grass fibre, with Which finding only 4% at Naked Sprout and 2.7% at Bumboo.
Instead, most of the material was found to contain eucalyptus, with Bazoo and Bumboo's samples containing acacia, a wood that has been associated with damaging deforestation in Indonesia.
Bamboo toilet paper samples from Cheeky Panda and Who Gives a Crap (WGAC) were found to contain only bamboo, as the makers claimed.
"While these brands may not have gone out to deliberately mislead consumers, it’s not good enough," said Which?
"Shoppers choosing these products are often doing so specifically because they are trying to be more sustainable. Yet, if the pulp being used isn't what it's supposed to be, the final product could be less sustainable than it appears."
The Forest Stewardship Council, which provides certification for products made by the three brands, said it has since contacted them and alerted its supply chain integrity team.
Bumboo responded to the findings by saying it "identified an issue in our supply chain and taken swift action so this can never happen again"
It also said: ‘Recycled paper and alternative fibres such as bamboo are still a better solution for the planet than using virgin trees.
Bazoo said its bamboo manufacturer is 100% FSC-certified and this is checked and audited every six months, and it is investigating this currently with the FSC body and its manufacturer in depth.
Naked Sprout also said it has a strict audit trail as used by the FSC, with all its production materials FSC certified and fully traceable from raw material to end product.
It disputed the objectivity and validity of the test method.
Fibre testing specialist TAPPI (the Technical Association of the Pulp and Paper Industry) said that it saw no contradictions in Which?’s application of the test method and that it “seems disingenuous” to suggest that a test method applied successfully to other brands tested would be inadequate for Naked Sprout.