Plastic drinking straws will be banned in England from next April.

In light of “overwhelming public support”, the government recently confirmed the new law, which aims to reduce the “environmental impact” of straws.

But does the ban make sense? How much environmental impact do straws actually have?

The government claims that as many as 47 million straws enter the sea from the UK each year. But FactCheck can reveal this was just an assumption – and the government appears to have no evidence to back it up.

Why ban straws?

Straws became the focus of public attention following David Attenborough’s Blue Planet series, which showed how plastic waste was harming marine wildlife.

Earlier this year, the then Environment Secretary Michael Gove explained the straw ban saying: “Our precious oceans and the wildlife within need urgent protection from the devastation throw-away plastic items can cause.”

And when the the Department for Environment, Food and Rural Affairs (Defra) published its official Impact Assessment document about the ban, saving the oceans was the very first explanation given. It said: “Plastic drinking straws are not commonly recycled or re-used, causing multiple environmental harms particularly when they are discarded incorrectly, including harm to marine animals and visual pollution.”

Defra are right to recognise marine plastic pollution as a problem. Some plastic straws from the UK do, of course, end up in the sea – and this can then damage wildlife.

But how many straws that end up in the sea are from the UK? Will this plastic straw ban make any difference?

‘Assumptions’

Defra’s Impact Assessment says: “We assume zero recycling occurs”. Instead, it claims: “99.9% of plastic straws are given to waste or are littered, and then collected by local authorities.”

A spokesperson told us this assumption was made because of the effort required to segregate and clean straws – and the fact that they are often too small to make their way through recycling systems to be recycled.

But is it true that no straws are recycled?

McDonald’s – which was previously one of the largest users of plastic straws – has said its plastic straws were “100% recyclable”. (Of course, that fact alone does not mean McDonald’s straws actually were being recycled, but it does raise questions about Defra’s assumption).

And the assumptions don’t end there.

Defra’s Impact Assessment claims that 0.1% of straws end up in marine environments. It explains that this is a “central estimate”, with 0.01% given as the lower estimate and 1% as its high estimate.

However, FactCheck has discovered that these figures are also just assumptions. The government was unable to provide us with any calculations or scientific evidence to back them up.

For the lowest estimate (0.01%) the Impact Assessment cites an independent report prepared for the government. This report says: “An assumption is used that 0.01% of items placed on market become marine litter. This is based on the ones which are terrestrially littered, not cleaned up and finally find their way into combined sewers and watercourses and the sea.”

There is no solid evidence behind even the lowest estimate. But the government’s Impact Assessment then multiplied this figure by ten to reach its central estimate – and by 100 to make its high estimate.

The government told us their reason for doing this was that the low estimate does not include straws that are littered directly into the ocean. But remember, this low estimate is merely an assumption – so it’s impossible to say whether it underestimates the number of straws going in the sea.

A spokesperson (speaking before Boris Johnson’s new government was formed) confirmed that the central and high estimates are also just assumptions.

It is also worth noting that the range between low and high estimates is enormous.

The Impact Assessment says that 4.7 billion straws are consumed in England each year. That means the government’s low estimate is of fewer than half a million straws entering the sea each year. But the top estimate puts that figure at 47 million.

UK plastic straws in context

When compared to global plastic pollution levels, UK’s plastic straw consumption is almost negligible.

According to one study, published in 2015, more than half of the world’s marine plastic pollution entered the ocean from just five countries: China, Indonesia, Philippines, Vietnam and Sri Lanka. By comparison, the combined total of every coastal EU country only ranks 18th globally. And of course, the UK is just one of 28 EU member states

Reports also suggest that, globally, straws only make up around 0.00002 per cent of all marine plastic pollution (in terms of weight). However, because they usually float, they are perhaps more likely to wash up onto beaches.

Nevertheless, the UK government says it wants to be a world-leader in this area. And whatever the exact figures, there is no doubt that banning plastic straws may reduce marine plastic pollution – albeit by a very small amount.

What are the downsides of the ban?

The plastic straw ban is far from uncontroversial: many disabled and elderly people rely on plastic straws, which are safer and more durable than any alternatives.

The government plans to allow exemptions in hospitals and for people who need them for medical reasons. But some disability rights campaigners are still critical, fearing it will be a “huge inconvenience”.

Dr Ted Henry, professor of Environmental Toxicology at Heriot Watt University, told FactCheck: “The government needs to recognise that the scale of this challenge of plastics is very large – and don’t simply look for quick fixes.”

He added: “It is perhaps appropriate that some plastics could be banned, but that should only be considered very carefully when other alternatives don’t make sense. But there are some situations where plastics are the best materials for certain applications – and we simply need to look at a different way of dealing with the plastic waste issue.”

“The topic of plastics – how we use plastics, how we dispose of plastics – is a very complicated one and there’s not going to be one solution that is going to solve all the problems.”

The government’s Impact Assessment only considers two options: banning straws, or not banning straws. It does not look at other measures, such as cracking down on littering.

The verdict

In order to back-up its ban on plastic straws, the government has used statistics that appear to be based on zero evidence.

This is perhaps unsurprising, given the lack of data and research on this issue. Nevertheless, justification for the ban seems to partly rely on unverified assumptions.

There’s no denying that a ban on plastic straws is likely to reduce the number entering the sea from the UK a bit. But we have no real firm idea about how much the reduction will be.

And the limited evidence available suggests that – compared to global levels of plastic in the sea – the number of straws entering from the UK barely registers on the scale.