The World Health Organisation (WHO) is launching a plastic health review after nearly every branded bottle of water tested in the largest investigation of its kind contained tiny particles of the material.

Scientists who carried out the examination of more that 250 bottles from nine countries said their analysis found plastic “in bottle after bottle and brand after brand”.

The tests, which were conducted at the State University of New York in Fredonia, found that there were typically 10 plastic particles per litre of bottled water. Each particle is larger than the width of a human hair.

Now the WHO is set to assess the research into the impact of so-called microplastics. The alarming findings came from research led by journalism organisation Orb Media.

There is no evidence that consuming such small particles of plastic has any ill health effects, but it comes at a time of heightened international concern of plastic pollution and the effect it is having on the environment.