Coca-Cola bottles and cans were the most prevalent branded litter on beaches in the UK, a report has found, as campaigners call on the government to get on with introducing a deposit return scheme.

Almost two-thirds (65%) of all branded packaging pollution across the UK coastline can be traced back to just 12 companies, according to the findings by the marine conservation charity Surfers Against Sewage (SAS).

These are Coca-Cola, PepsiCo, AB InBev, McDonald’s, Mondelez International, Heineken, Tesco, Carlsberg Group, Suntory, Haribo, Mars and Aldi.

In total 3,913 volunteers collected branded items over 11,139 miles, making it the UK’s biggest coordinated cleanup event. SAS recorded a total of 9,998 branded items that were linked to 328 companies.

Hugo Tagholm, the charity’s chief executive, said: “Our annual Brand Audit [report] has once again revealed the shocking volume of plastic and packaging pollution coming directly from big companies and some of their best-known brands … Legislation such as an ‘all-in’ deposit scheme needs to be introduced urgently and governments need to hold these companies to account and turn off the tap of plastic and packaging pollution flooding the ocean.”

Companies say that a lack of a good deposit return scheme (DRS) in the UK means the packaging of their products gets needlessly littered.

There are plans for such a scheme in Britain, but this has been delayed until 2024 – with the government blaming the Covid-19 pandemic.

In a DRS consumers are charged an additional deposit fee when they buy a drink in a single-use container. This deposit acts as an incentive to support recycling because it is redeemed when the consumer returns the empty container to a return point.

A spokesperson for Coca-Cola said: “Like everyone, we care about reducing packaging waste and we don’t want to see any of our packaging end up where it shouldn’t. All of our packaging is 100% recyclable and our aim is to get more of it back so that it can be recycled and turned into new packaging again.

“It’s disappointing to see any packaging being littered and that’s why we support the introduction of a well-designed deposit return scheme, which would encourage people to recycle rather than litter or throw away. In Great Britain, we’re continuing to work with numerous organisations to encourage more recycling on-the-go and we’re actively supporting a number of initiatives with the aim of making litter something of the past.”

Andrew Opie, the director of food and sustainability at the British Retail Consortium, said: “Supermarkets are working quickly to remove unnecessary plastics from their stores, having already removed all polystyrene packaging and plastic cutlery, as well as trialling packaging free and refillable options. This helps explain how supermarkets achieved a drop in the amount of plastic across their own brand products.

“More needs to be done and retailers have set themselves challenging reduction targets and are committed to ensuring all packaging will be 100% reusable, recyclable or compostable in the future. However, government and local councils must play their part by improving our current recycling infrastructure, and better enforcing laws against irresponsible littering.”

SAS is calling for companies to reduce their packaging and switch to refill models as well as the all-in return scheme. The Brand Audit report estimates that more than half (52%) of the pollution from the “dirty dozen” companies would be captured through such a scheme, including 80% of Coca-Cola’s products.

Despite the ubiquity of single-use personal protective equipment such as face masks during the Covid crisis, this made up a tiny fraction of the litter found.

Tagholm said: “Despite the surge in single-use plastic as a result of the pandemic, PPE made up just 2.5% of unbranded plastic pollution recorded during our latest Brand Audit. We cannot allow polluting industries to use the current health crisis to deflect from their own damaging behaviours and put the blame on the individual – we must demand action now.”