“Eight million tonnes of plastic are discarded into the world’s oceans each year, putting marine wildlife under serious threat,” Environment Secretary Michael Gove told a meeting at WWF UK as he announced the decision, following a consultation period.

He said a start had been made to rectify the situation with the 5p carrier-bag charge introduced in October 2015, and described this as an “enormous success”, cutting by 9 billion the number of plastic bags distributed, an 83% drop. He said that the charge had raised more than £95m that had been donated to good causes.

Gove also said that, as part of a renewed strategy on waste and resources linked to leaving the European Union, the Government would explore new methods of reducing the amount of plastics, in particular bottles, entering UK seas, improve incentives for reducing waste and litter, and review penalties available to impose on polluters.

An expert group had begun considering the pros and cons of different types of deposit and reward-and-return schemes for plastic containers.

Environmental activists Greenpeace responded enthusiastically to Gove’s announcement by saying that: “The UK Government just proposed the strongest ban on microbeads in the world to date. This is great news for our environment and a positive sign of Britain’s global leadership on ocean plastics.

“We still need to keep an eye on the details on the ban in legislation coming forward this autumn. But the announcement from the Government today made clear that the ban does cover so-called biodegradable plastics (as there’s no evidence that these actually do biodegrade in the marine environment) and that all personal care and cosmetic products containing microbeads will be off the shelves by 30 June, 2018 – one day before the same happens in the USA.”

Greenpeace said that it was “crucial that ministers have left the door open to broaden the ban in future to all products that go down the drain.”

It also welcomed Government support for the introduction of a deposit-return scheme for plastic bottles in England, following progress and what it described as strong political support in Scotland.

The Marine Conservation Society (MCS) campaigned with Greenpeace, the Environmental Investigation Agency and Fauna & Flora International over the past 18 months to obtain the microbead ban.

“It is a hugely important first step,” said MCS Head of Pollution Dr Laura Foster. “However, there are lots of products that are not included in the ban which will continue to be made and sold that contain microplastic ingredients.

"The next step should be to consider extending the scope of the ban to more products such as suncreams and make-ups that are in common use.”

*  MEANWHILE A FURTHER indication of the extent of the problem of ocean pollution has come with a report that a vast “gyre” or accumulation of plastic debris has been located in the South Pacific.

Researchers believe that it could cover as much as 1 million square miles, or the size of Kazakhstan.

Like the gyre previously found in the North Pacific, this one has been formed by currents and winds combining to concentrate waste in a single area.

The report comes from the Algalita Marine Research Foundation, working primarily in an area around Easter and Robinson Crusoe islands, though it has yet to publish a formal paper.

It says that most of the plastic debris is in the form of fragments smaller than rice-grains, which can easily pass into the food-chain.

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