Responding to a question about the potential merits of a ban, fellow environment minister George Eustice said last week: "Microbeads from personal care products are believed to make up a very small percentage of the total amount of microplastics entering the marine environment, with estimates ranging from 0.01 per cent to 4.1 per cent.

"A ban in the UK would therefore be expected to have only a small impact on the effects on the environment attributed to microplastics.

"However, microbeads, like other microplastics, do not biodegrade and so accumulate in the marine environment. There are also less harmful alternatives that are suitable to use.

"Defra supports voluntary action by industry to phase out microbeads from personal care products, and is supporting other EU Member States in calling for the European Commission to come up with proposals to ban their use in cosmetics and detergents."

Louise Edge, oceans campaigner with Greenpeace UK, said Mr Stewart's comments were "the first time we have heard the UK government publicly say they are open to a possible ban on microbeads".

"This is great to hear and is reflective of the opinion of hundreds of thousands of people across the country who have called for such action," she said.

However Kerry McCarthy MP, Labour's shadow environment secretary, who has been calling for a ban, suggested that Mr Stewart's reference to unilateral UK action might only mean implementing a voluntary scheme.