The oil industry is investing £300bn in producing more plastic over the next five years, despite public pledges to reduce their net carbon emissions to zero and action from governments to cut plastic waste, a new report has found.

The cash that firms plan to pump into increasing plastic production dwarfs the sums they have collectively earmarked for a transition to renewable energy.

With demand for fuel expected to fall sharply as vehicles are electrified, oil majors are pinning their hopes for future growth on a huge expansion of plastic use, with much of it expected to come in developing countries.

Environmental think tank Carbon Tracker, which carried out the research with consultancy Systemiq, described the industry’s projections as “delusional” and said they could result in hundreds of billions of pounds being spent on useless chemical plants making plastic that no one wants.

“When it comes to plastics, there is an enormous divide between what oil the industry wants and what society demands,” said Kingsmill Bond, energy strategist at Carbon Tracker and the report’s lead author.

Surveys in 28 countries last year found that between 70 and 80 per cent of people wanted action on waste including a ban on single-use plastic and forcing manufacturers to pay for recycling costs.

Governments around the world have stepped up their efforts to slash plastic waste in response to increased awareness of the toxic legacy it leaves in crops, land, oceans and even in the human body.

That global push is expected to see plastic recycling increased sharply from the current level of just 5 per cent, reducing demand for virgin plastic.

The European Union plans to introduce a tax of €800 (£714) per tonne of new plastic to cover the environmental costs of recycling and disposal, with similar measures being mooted in other countries including China.

In a sign that the tide is turning on plastic, China closed down most of its industry for importing and processing plastic waste in 2018, forcing other countries including the UK to look elsewhere to solve the problem.

“The oil industry has polluted with impunity for 70 years but now they are going to be made to pay, by hook or by crook, for the huge costs that puts on society,” Mr Bond added.

“Remove the plastic pillar holding up the future of the oil industry, and the whole narrative of rising oil demand collapses.”

Systemiq estimates that each tonne of plastic generates £1,000 of “externality” costs which are not borne by the producer, such as recycling, cleaning up oceans and beaches, health impacts and CO2 emissions.

The report’s authors estimate that without urgent action, the amount of plastic waste flowing into oceans could triple by 2040.

They put forward a set of proposals to cut demand through measures such as better product design, substituting paper for plastic and massively increasing recycling.

By Systemiq’s calculations, these measures would not only drastically reduce the environmental impact but would mean provide the same amount of usable plastic in circulation at half the capital cost while creating jobs.

Yoni Shiran, who leads Systemiq’s work on plastics and co-authored the report, said: “There are huge benefits in the change from the current linear system to a more circular one.

“You can have all the functionality of plastics but at half the capital cost, half the amount of feedstock, 700,000 additional jobs and 80 per cent less plastic pollution.”

Under this scenario, demand for new plastic would peak in 2027, removing the main driver of growth in oil production that fossil fuel companies are forecasting.

This makes it more likely that oil demand will have peaked in 2019, according to the report.

Projections for a massive increase in plastic production are difficult to square with the Paris Agreement or oil companies’ own pledges to reach net zero emissions.

Each tonne of plastic releases twice as much CO2 as the same amount of oil because gases are emitted at the production stage and when the plastic is disposed of.

If the oil industry produces as much plastic as it forecasts, emissions from plastic would double to 3.5 gigatonnes, .

The amount is more than 10 per cent of the total emissions from global energy supply in 2018 and more than one-fifth of the carbon budget for the energy sector in 2030.

“It is simply delusional for the plastics industry to imagine that it can double its carbon emissions at the same time as the rest of the world is trying to cut them to zero,” Mr Bond said.