The Texas-based company, Energy Transfer, alleges protest tactics by Greenpeace delayed the project, which began transporting oil in 2017 after President Donald Trump backed in his first term.

Protests against the pipeline near the Standing Rock Sioux Reservation drew thousands, but Greenpeace says it did not lead them and the lawsuit threatens free speech. The organisation “could face financial ruin, ending over 50 years of environmental activism” if it loses, it also says.

The trial in North Dakota is expected to last five weeks, beginning with jury selection on Monday.

The lawsuit, filed in state court, accuses Greenpeace of an “unlawful and violent scheme to cause financial harm to Energy Transfer, physical harm to its employees and infrastructure, and to disrupt and prevent Energy Transfer’s construction of the Dakota Access Pipeline”.

Greenpeace says it could be forced into bankruptcy if it is ordered to pay the approximate $300m (£237m) in claimed damages.

Energy Transfer brought a similar federal lawsuit in 2017, arguing protesters had violated the Racketeer Influenced and Corrupt Organizations Act (Rico) – an allegation more often made against organised crime groups. A judge dismissed the case.

But this trial is taking place in conservative North Dakota.

The state’s former governor, Doug Burgum, is currently leading the federal agency on public lands for the Trump administration, as the secretary for the Department of Interior. Greenpeace has expressed concern that it cannot get a fair hearing in the oil-rich area.

The pipeline’s construction gained international attention during Trump’s first term as Native American groups set up an encampment trying to block it from passing near Standing Rock. The protests started in April 2016, and ended in February 2017, when the National Guard and police cleared the protest site.

At the peak, over 10,000 protesters were on site. The group included more than 200 separate Native American tribes, hundreds of US military veterans, actors and political leaders – including the current health secretary, Robert F Kennedy, Jr.

Hundreds were arrested, and authorities were accused of using excessive force, including dousing crowds with pepper spray and freezing water as well as firing sound cannons, bean-bag rounds and rubber bullets.

Lawyers for Greenpeace argue that it was not the leader of the protest group, but helped support “nonviolent, direct-action training” to protesters.

The suit names Greenpeace USA, as well as its Washington DC-based funding arm Greenpeace Fund Inc and its Amsterdam-based parent group Greenpeace International.

Greenpeace has sued Energy Transfer (ET) in Dutch court, claiming that the company is attempting to unfairly use the legal system to silence critics.

The lawsuit, filed earlier this month, seeks to recover “all damages and costs it has suffered as a result of ET’s back-to-back, meritless lawsuits”.

The charity has agreed to pay £300,000 to the RNLI after campaigners climbed onto the floating production vessel while it was being transported to the Penguins field north east of Shetland last year.

The protesters have also agreed not to return to four Shell platforms.

Greenpeace has accused Shell of using “bullying tactics” against peaceful protest while the oil giant says the stunt posed a serious risk to life.

Greenpeace activists boarded the White Marlin ship north of the Canary Islands in the Atlantic in January 2023 and occupied it for 13 days.

Activists campaigning against fossil fuels and oil drilling used inflatable boats to reach the Shell-contracted ship, before hoisting themselves onto it with ropes.

Following the settlement, Greenpeace said it would continue to campaign against Shell, including in the North Sea.

Areeba Hamid, co-executive director at Greenpeace UK, said: “Shell thought suing us for millions over a peaceful protest would intimidate us, but this case became a PR millstone tied around its neck.

“The public backlash against its bullying tactics made it back down and settle out of court.”She added: “This settlement shows that people power works. Thousands of ordinary people across the country backed our fight against Shell and their support means we stay independent and can keep holding Big Oil to account.

“We’ve ensured not a penny of our supporters’ money will go to Shell and all funds raised will be used to continue campaigning against the fossil fuel industry and other big polluters.”

A Shell spokesperson said: “Shell is pleased that the dispute has been settled and that a payment in lieu of the costs it incurred can benefit a charity working on safety at sea.”

For Shell, the right to protest is fundamental and has never been at issue. Instead, this case was about an illegal boarding by protesters which a High Court judge described as “putting their lives and, indirectly, the lives of the crew at risk”.

“He was also clear that Greenpeace could still protest from a safe distance and their human rights were not infringed.”

Shell was originally suing Greenpeace for £1.7m in damages.