The UK’s competition watchdog has opened an investigation into whether Unilever is making environmental claims that do not stack up when marketing some of its cleaning products and toiletries.

The Competition and Markets Authority (CMA) said it had found “a range of concerning practices” after investigating the £140 billion fast-moving consumer goods market.

It is now launching a formal investigation into Unilever, one of the largest players in the sector which makes products such as Cif, Dove, Comfort and Lynx.

The CMA said that some of the statements and language used by Unilever “appear vague and broad” and might mislead shoppers about the products’ environmental impact.

Unilever's use of colours and imagery - such as green leaves - may create the overall impression that some products are more environmentally friendly than they actually are

“Claims about some ingredients are presented in a way that may exaggerate how ‘natural’ the product is, and so may create an inaccurate or misleading impression,” the CMA said.

It also said that claims about a product being recyclable could sometimes be unclear, not saying whether it is for the whole product, part of it, or just the packaging it is in.

The watchdog added: “Unilever’s use of colours and imagery – such as green leaves – may create the overall impression that some products are more environmentally friendly than they actually are.”

As shoppers get increasingly keen to make choices that they think have a lower impact on the environment, many companies have scrambled to market their products as greener than the competition.

But campaigners have warned that many of these claims often simply do not stack up and are just marketing without basis in fact.

Last month campaign group Greenpeace called on Unilever to phase out single-use plastics from its operations in the next 10 years.

CMA chief executive Sarah Cardell said: “Essentials like detergent, kitchen spray and toiletries are the kinds of items you put in your supermarket basket every time you shop.

“More and more people are trying to do their bit to help protect the environment, but we’re worried many are being misled by so-called ‘green’ products that aren’t what they seem.

We are surprised and disappointed with the CMA’s announcement and refute that our claims are in any way misleading

“So far, the evidence we’ve seen has raised concerns about how Unilever presents certain products as environmentally friendly.

“We’ll be drilling down into these claims to see if they measure up. If we find they’re greenwashing, we’ll take action to make sure shoppers are protected.”

Unilever said: “We are surprised and disappointed with the CMA’s announcement and refute that our claims are in any way misleading.

“Unilever is committed to making responsible claims about the benefits of our products on our packs and to these being transparent and clear, and we have robust processes in place to make sure any claims can be substantiated.

“We use the on-pack recycling label (OPRL) to provide consumers with information on how to dispose of our packaging after use, and Unilever is a founding signatory of the UK Plastics Pact, which brings together the entire plastics packaging value chain to tackle the challenges around plastic waste.

“We will continue to co-operate with the CMA and fully comply with further requests for information.”