Close to half of green claims made by companies could be misleading, according to a new study by competition regulators around the world.

The UK’s Competition and Markets Authority, and others across the globe, analysed around 500 websites promoting products and services.

It found that four in 10 of the websites were using tactics that could be considered misleading and potentially broke consumer law.

Too many websites appear to be pushing misleading claims onto consumers, which means that companies offering products with a genuine environmental benefit are not getting the customers they deserve

They included making vague claims and unclear language, such as attaching labels like “eco” or “sustainable”, without explaining what this meant.

The regulators also aimed criticism at own-brand eco labels which were not connected to any established group, meaning the company had set its own goalposts.

Other websites hid or omitted certain information, including pollution levels, in a bid to seem more eco-friendly.

Our joint work with other regulators will help us identify the big issues facing consumers and protect people from paying a premium for fake ‘eco-friendly’ products

“Too many websites appear to be pushing misleading claims onto consumers, which means that companies offering products with a genuine environmental benefit are not getting the customers they deserve,” CMA chief executive Andrea Coscelli said.

“People should be able to easily choose between those companies who are doing the right thing for the environment and those who are not.

“This is a global issue, so it’s only right that we look at it in a global context. Our joint work with other regulators will help us identify the big issues facing consumers and protect people from paying a premium for fake ‘eco-friendly’ products.”

The CMA said that it and the other members of the International Consumer Protection Enforcement Network (ICPEN), which ran the study, had not yet decided whether they thought consumer law had been broken.

The CMA said that if it found evidence that businesses were misleading UK consumers, it would take action.

Practices flagged for concern included baby wipes that claimed to have “0% plastic” in them, but without saying if this included both product and packaging, a milk substitute which claimed to be “sustainably sourced” without supplying any more information to back this up, and a high street retailer marketing clothes as “recycled cotton” without saying what proportion of cotton was recycled.