British Prime Minister Gordon Brown is expected to propose rules within the next year aimed at reducing the ubiquity of single-use plastic bags in the United Kingdom. About 13 billion plastic bags are given out free to U.K. shoppers every year and many are only used once before getting thrown out; plastic bags can take up to 1,000 years to biodegrade. Brown has called on supermarkets and other retailers to take voluntary measures like charging a 5-pence fee for each plastic bag or moving away from single-use plastic bags altogether. The prime minister hinted that if retailers’ voluntary measures don’t result in large enough reductions, plastic-bag-reduction programs of one kind or another could become mandatory.