British firms are still selling wood products that come from questionable sources in parts of the world where illegal logging is having a devastating effect, a new study has revealed.

The report found that wood used in kitchen worktops, doors and decking, on sale in the UK, comes from parts of Indonesia, Malaysia and the Congo Basin where illegal felling is putting animals, plants and people under threat. Numerous species, including the orangutan, are under direct threat of extinction because of the black market trade in timber.

The "What Wood You Choose?" study suggested British businesses aren't checking their sources and in some cases are even misleading the public that the wood they are selling has ethical credentials where none exist.

New EU timber laws are due to come into force next year, but this WWF-funded study shows few retailers are prepared for the legislation which could leave them open to conviction. The study found that in some cases companies had little idea where their wood products originated from and were reluctant to find out.

It also found that some companies' websites were misusing the Forest Stewardship Council (FSC) logo, implying that all their products are covered by the certification scheme when in fact only some are. WWF used a combination of formal requests, investigators posing as buyers and made phone calls and visits to sawmills in Indonesia and Malaysia to track timber products.

Colin Butfield, WWF's head of campaigns, said: "This study should act as a wake-up call to companies here in the UK. Consumers are the ones with the power to demand that whatever they're buying, from doors to kitchen worktops, is FSC [certified]. If it doesn't have the FSC logo then it could originate from a place where there have been devastating impacts on species, such as the orangutan, and communities that earn a living from the forest.

"The EU law, coming into force in early 2013, will mean anyone intending to sell timber products into the UK market will have to show where it's come from and that it isn't illegal. The study suggests that UK businesses are a long way from meeting the demands of that new law."