The number of plastic bags found on the seabed has plummeted, suggesting efforts to combat plastic pollution are working.

Government scientists compiled data on 25 years’ worth of plastic trawled from the bottom of the sea to examine litter trends in the waters surrounding the UK.

While the findings have been heralded as evidence of successful policies to reduce plastic pollution, experts say the report shows that other items need to be dealt with as vigorously as plastic bags.

Despite the reduction in carrier bags, the overall amount of deep-sea litter remained roughly constant due to an increase in the number of other plastic items, including bottles and fishing debris.

The new research comes shortly after another report produced for the government that concluded the amount of plastic in the world’s oceans is set to treble within a decade.

Pledging to tackle this “scourge”, the government has implemented various measures to deal with plastic waste – most recently bottle deposit schemes.

Charges on supermarket carrier bags have led to an 80 per cent drop in plastic bag use across England, and ministers have hailed this move as a victory in the war on plastic waste.

The scientists behind the new research at the Centre for Environment, Fisheries and Aquaculture Science (Cefas) have suggested the trend they observed on the sea floor could be partly a result of this action.

“It is encouraging to see that efforts by all of society, whether the public, industry, NGOs or government to reduce plastic bags are having an effect,” said Dr Thomas Maes, a marine litter scientist at Cefas and the report’s lead author.

Plastic waste across the world: in pictures Show all 15 1 /15 Plastic waste across the world: in pictures Plastic waste across the world: in pictures A father and son on a makeshift boat made from styrofoam paddle through a garbage filled river as they collect plastic bottles that they can sell in junkshops in Manila. The father and son team earn some three US dollars a day retrieving recyclables from the river. AFP/Getty Plastic waste across the world: in pictures A composite image of items found on the shore of the Thames Estuary in Rainham, Kent. Tons of plastic and other waste lines areas along the Thames Estuary shoreline, an important feeding ground for wading birds and other marine wildlife. Getty Images Plastic waste across the world: in pictures Children collect plastic water bottles among the garbage washed ashore at the Manila Bay. According to the United Nations Environment Programme, at current rates of pollution, there will likely be more plastic in the sea than fish by 2050. AFP/Getty Plastic waste across the world: in pictures Plastics and other detritus line the shore of the Thames Estuary. In December 2017 Britain joined the other 193 UN countries and signed up to a resolution to help eliminate marine litter and microplastics in the sea. It is estimated that about eight million metric tons of plastic find their way into the world's oceans every year. Once in the Ocean plastic can take hundreds of years to degrade, all the while breaking down into smaller and smaller 'microplastics,' which can be consumed by marine animals, and find their way into the human food chain. Getty Plastic waste across the world: in pictures A dump site in Manila in 2013. The Philippines financial capital banned disposable plastic shopping bags and styrofoam food containers, as part of escalating efforts across the nation's capital to curb rubbish that exacerbates deadly flooding. AFP/Getty Images Plastic waste across the world: in pictures Children swims in the sea full of garbage in North Jakarta, Indonesia. Getty Plastic waste across the world: in pictures An Indian woman holds a jar filled with Yamuna river water polluted with froth and toxic foam to be used for rituals at the river bank in New Delhi, India. The Yamuna River, like all other holy rivers in India, has been massively polluted for decades now. The river that originates in a glacier in the pristine and unpolluted Himalayas, and flows through Haryana, Delhi and Uttar Pradesh before merging with the Ganges River in Allahabad, once used to be the lifeline of the Indian capital. Currently, it is no more than a large, open sewer that is choking with industrial and domestic discharge that includes plastic, flowers and debris and has virtually no aquatic life. EPA Plastic waste across the world: in pictures Plastic waste is washed up on South Troon beach in Scotland. Recent reports by scientists have confirmed, plastics dumped in the world oceans are reaching a dangerous level with micro plastic particles now being found inside filter feeding animals and amongst sand grains on our beaches. Getty Plastic waste across the world: in pictures Children collect plastic to be sold and recycled, in a polluted river in suburban Manila. The city's trash disposal agency traps solid waste floating down waterways that was thrown into the water by residents of slums along riverbanks upstream. AFP/Getty Plastic waste across the world: in pictures View of the Carpayo Beach in La Punta, Callao, some 15 km of Lima. In 2013, the NGO VIDA labeled the Carpayo Beach as the most polluted in the country - 40 tons of trash on each 500m2. AFP/Getty Plastic waste across the world: in pictures Trash from Kamilo Beach in Hawaii. Gabriella Levine/Flickr Plastic waste across the world: in pictures A scavenger collects plastic cups for recycling in a river covered with rubbish near Pluit dam in Jakarta. Reuters Plastic waste across the world: in pictures Rubbish fills Omoa beach in Honduras. Floating masses of garbage offshore from some of the Caribbean's pristine beaches are testimony to a vast and growing problem of plastic pollution heedlessly dumped in our oceans, locals, activists and experts say. AFP/Getty Plastic waste across the world: in pictures A man climbs down to a garbage filled river in Manila. Plastic rubbish will outweigh fish in the oceans by 2050 unless the world takes drastic action to recycle the material, a report warned in 2016. AFP/Getty Plastic waste across the world: in pictures Garbage on East Beach, Henderson Island (Pitcairn Islands), in the south Pacific Ocean. The uninhabited island has been found to have the world's highest density of waste plastic, with more than 3,500 additional pieces of litter washing ashore daily at just one of its beaches. EPA

“We observed sharp declines in the percentage of plastic bags as captured by fishing nets trawling the seafloor around the UK compared to 2010 and this research suggests that by working together we can reduce, reuse and recycle to tackle the marine litter problem.”

The findings by Dr Maes and his colleagues were based on the analysis of nearly 2500 ocean trawls conducted by ships between 1992 and 2017.

Over the entire 25-year period, more than 60 per cent of all trawls contained plastic litter. These results were published in the journal Science of the Total Environment.

Past research has found plastic to be pervasive across marine ecosystems, with litter found at the poles and at the bottom of deep sea trenches.

The impact of plastic in the marine environment is still poorly understood. However, animals are known to die after consuming or becoming tangled in litter, and plastic has even been implicated in spreading diseases around coral reefs.

In Theresa May’s 25-year environment plan, launched in January, she said the success of the 5p plastic bag charge “shows the difference which government action can make”.

Since then, minsters have considered the introduction of a similar charge on disposable coffee cups, as recommended by the Environmental Audit Committee.

Such measures have been backed by The Independent’s own Cut the Cup Waste campaign, which found the majority of the British public would be in favour of a 25p charge added to coffee cups.

However, ministers rejected the levy proposal in March, drawing criticism from environmental organisations.

Mary Creagh, who chairs the committee, said the new evidence from Cefas supported the need for such a levy.

Latte levy: The plastic problem inside your coffee cup

“This research shows how effective charges are at reducing plastic waste,” she said.

“The UK has used 9 billion fewer plastic bags since the 5p charge was introduced. Ministers should introduce a 25p ‘latte levy’ to tackle the UK’s mountain of coffee cup waste.”

This sentiment was echoed by environmentalists, who welcomed the apparent decline in plastic bags but urged the need for further action.

“It’s great that the bag levy appears to have cut plastic bags in our seas, but much tougher action is needed if we’re to tackle the huge plastic pollution crisis – including microplastics – swamping our marine environment,” said Friends of the Earth plastics campaigner Julian Kirby.

“Our seabeds are becoming dumping grounds for plastic, which is proving devastating for wildlife. Out of sight, shouldn’t mean out of mind,” said Dr Lyndsey Dodds, head of marine policy at WWF.

“Taxes and levies are a good step – the reduction in plastic bags entering the ocean is proof of this – but we need the government to be thinking bigger and putting an end to the use of all avoidable single-use plastic by 2025.”

Commenting on the Cefas report, a spokesperson from the Department for Environment, Food and Rural Affairs said: “This report clearly shows our 5p plastic bag charge has made a significant impact in reducing plastic in our oceans, taking 9 billion bags out of circulation since it was introduced.