US law enforcement officers used British anti-riot gear to strike protesters during their controversial policing of Black Lives Matter demonstrations, despite assurances from the Conservative government that no UK-made equipment was used to repress peaceful protest.

Officers deployed at demonstrations in Washington DC hit protesters and in one case a journalist using shields made by the British-based firm DMS Plastics. Video and photographs suggest, and a lawsuit alleges, that officers charged at protesters, rather than acting in self-defence. US forces deny the allegations.

Images from late May and June show a number of incidents of law enforcement units holding Scorpion-brand shields made by DMS, including the US park police, the Secret Service and Arlington county police. Footage shows officers using the shields to repel crowds, with instances of people being struck with the shields without any apparent justification.

The findings come as part of a joint investigation tracking British-made weaponry and personal protective equipment around the world by the Guardian, Sky News and the investigative outlet Bellingcat, organised by the media nonprofit organisation Lighthouse Reports.

A group of protesters represented by the American Civil Liberties Union is suing US President Donald Trump, attorney general William Barr, defense secretary Mark Esper and the heads of US police and security forces over alleged use of force at a peaceful demonstration near the White House on 1 June.

Officials had “no legitimate basis to destroy the peaceable gathering”, they allege, describing the action as a “manifestation of the very despotism against which the first amendment was intended to protect”. The lawsuit mentions instances of officers using anti-riot shields as part of an escalation in tactics. “The officers hit, punched, shoved, and otherwise assaulted the demonstrators with their fists, feet, batons, and shields,” they added.

Concerns over the aggressive response to BLM demonstrations led parliamentarians in Edinburgh and Westminster to question British sales of riot-control equipment to the US, including tear gas. The British government agreed to review licences for sales of anti-riot gear but later rejected any suggestion that sales should be halted, and dismissed questions from the legal representative of a black British citizen who challenged the government over crowd control equipment sales.

Treasury lawyers told the law firm Deighton Pierce Glynn on 24 July that officials carried out a temporary suspension and reassessment of licences for anti-riot gear in the wake of the US demonstrations, with explicit mention of anti-riot shields. They stated that there was “no evidence that equipment licensed by the UK was used during the protests”.

They added that “given the broad list of end users covered by the licences”, it was possible that equipment could have been used against protesters. In images from cities across America, British-made shields were visible, and apparently misused in confrontations with protesters.

The US protests, and the controversy over their policing, began after the 25 May killing of George Floyd, an African American man who died in Minneapolis while a white police office knelt on his neck. One of a catalogue of deaths of black men and women at the hands of white US police officers, it was a catalyst for the the largest civil rights uprising of the modern era.

On 1 June in Washington DC, officers fired tear gas on crowds of peaceful protesters before using force to clear the protest to let President Trump walk to a nearby church for a photo opportunity. The ACLU’s lawsuit challenging the clearing of the demonstration cites the case of US Navy veteran Kishon McDonald, who, it says, was “repeatedly struck by the shields of multiple officers which left bruises on his body. Officers continued to physically strike Mr McDonald even after he began to leave the site.”

Donald Trump et al. wearing costumes: President Donald Trump walks past police carrying British-made Scorpion shields in Lafayette Square, Washington DC, on 1 June. Photograph: Patrick Semansky/AP© Provided by The Guardian President Donald Trump walks past police carrying British-made Scorpion shields in Lafayette Square, Washington DC, on 1 June. Photograph: Patrick Semansky/AP
The brand of the shield involved in this case is not stated in the allegations.

Questions remain over whether using anti-riot shields to strike protesters constitutes fair use. Some law enforcement manuals say only that the shields are intended as protection from projectiles. The Washington DC Metropolitan Department tells officers that permitted force involves “hands-on touching or pushing maneuvers, but with no deployment of tools or weapons”, and “physical force may include line and wedge formations (with or without protective riot shields) that move a crowd”.

A lawyer acting for DMS Plastics emphasised that DMS manufactured the riot shields but could not “be responsible for any misuse of the PPE” that it made.

He said that DMS Protective Equipment, a sister company, was only responsible for distributing Scorpion-brand shields in the UK. All exports were via independent distributors in the relevant countries and any misuse of the Scorpion shields was “by a minute fraction of the US officers”.

Photographs from late May and 1 June show officers in Washington DC knocking different lone protestors to the ground using British-made Scorpion shields. Others show unarmed protesters with their hands up as officers appear to strike with shields and batons.

Footage broadcast live on Australia’s 7News channel on 1 June showed the correspondent Amelia Brace and cameraman Tim Myers charged by police brandishing Scorpion shields, before one officer hit Myers with a shield.

Brace testified before a US congressional committee in late June. “I’ve been shocked to see how many journalists have been attacked, beaten and detained, just for doing their jobs,” she said. Two US park police officers were “assigned administrative duties”, while an investigation into the attack on the journalists is carried out. US park police said in a statement at the time that the Australians “may have fallen”, and that because of the loud noise and the “lack of readily identifiable journalist markings”, the crew were not “readily indistinguishable from violent protesters”.

Video footage also shows a Utah police officer holding a Scorpion shield as he appears to shoot a protester in Salt Lake City with a smoke grenade at close range.

Roxeanne Vainuku of the West Valley City police department, said the protester was holding a bat not visible in the video. She confirmed that the department’s officers used Scorpion shields, among others, “for protection during protests”, adding that they were “used to protect officers against projectiles and to create distance between advancing persons and officers”.

The US park police told the Guardian that it “followed established procedures and regulations during the civil unrest that occurred near the White House in May and June. All use of force complaints are being investigated by our internal affairs unit.”

It also cited a statement issued by the acting US park police chief Gregory T Monahan defending the force’s actions and accusing protesters of being “combative”.

Arlington county police department’s spokeswoman Ashley Savage said it was “committed to supporting the peaceful expression of first amendment rights … our civil disturbance unit (CDU) is used only to maintain peace and order with crowds experiencing unrest. These officers are highly trained and skilled in peaceful crowd control and dispersal.”

Arlington county withdrew its officers from Washington DC on 1 June after officers were “asked to take action that is inconsistent with our values”.

Asked about its involvement in policing Washington demonstrations, a Secret Service spokesperson said it had no comment.

British MPs have questioned the sale of anti-riot equipment to the US. In June, 166 MPs and the Scottish government demanded an end to such sales owing to the violent crackdown on peaceful protests, stating that UK-made equipment “could be misused”.

A database maintained by the UK-based Campaign Against Arms Trade records seven licences for British anti-riot equipment and arms exports to the US still in effect. In 2019, the UK issued licences for the sale of anti-riot shields worth at least £758,000 to the US. A parliamentary statement on 10 June detailed current licences for sales of anti-riot gear to the US, including two for “anti riot/ballistic shields”, to a total value of £850,000.

A Department for International Trade spokesperson said all export licences were under “careful and continual review”.

“The UK takes its export control responsibilities very seriously and operates one of the most robust and transparent export control regimes in the world,” the spokesperson said. “We rigorously examine each export licence application on a case-by-case basis against the consolidated EU and national arms export licensing criteria.”