The number of plastic bags washed up on UK beaches has fallen by 80% over a decade, since a mandatory fee was imposed on shoppers who opt to pick up single-use carrier bags at the checkout.

According to the Marine Conservation Society’s (MCS) annual litter survey, volunteers found an average of one plastic bag every 100 metres of coastline surveyed last year, compared to an average of five carrier bags every 100 metres in 2014.

The charity, which has monitored beach litter for the past three decades, said the drop was undoubtedly due to the introduction of mandatory charges, which can range from 5p to 25p, for single-use plastic bags.

Lizzie Price, Beachwatch programme manager at MCS, said: “It is brilliant to see policies on single-use plastics such as carrier bags working.”

Large retailers in Wales, Northern Ireland, Scotland and England have been required to charge for single-use plastic bags by laws introduced in 2011, 2013, 2014 and 2015, respectively. The charge was increased from 5p to 10p in 2021 for England and Scotland and is 25p in Northern Ireland. Wales, where the minimum charge remains 5p, has said it will ban the bags altogether by 2026.

Price urged the devolved UK governments to push forward with their policies to charge for, ban or reduce more single-use items, and take action such as speeding up the proposed deposit scheme for plastic bottles, cans and glass. All four UK nations have been working together to try to agree a joint approach to the scheme, which has now been delayed until 2027.

“We must move quicker towards a society that repairs, reuses and recycles,” said Price.

The number of plastic bags found along the coastline began to dramatically drop across the UK in 2015, according to the charity. In Scotland, the average number found was 11 per 100 metres in 2014, but had dropped to six in 2015, a year after the charge was introduced.

The MCS’s 2023 beach litter report, which included 1,199 separate surveys, found that 97% of beaches had drinks-related litter, such as bottle and cans. It found 4,684 plastic bags.

The society’s beach cleaning effort takes place all year round, but it collects a third of its data during its Great British Beach Clean events. Last year, thousands of volunteers found that drinks-related litter had increased by 14% in Scotland and 7% in England, compared with 2022. Overall, it recorded a 1.2 % increase in plastic litter across the UK, with an average of 167 items per 100 metres.

The most common five items found were plastic pieces measuring 2.5-30cm, packets such as crisp and sandwich wrappers, caps and lids, plastic string and cord, and plastic bottles and containers.

More than 100 litter-picks have been organised for this year’s Great British Beach Clean, which will take place 20-29 September on shores from Bude in Cornwall to Aikerness in the Orkney Islands.