Lilia Sebouai Global Health Security Reporter

The Government failed to intervene in a “genocidal” massacre in Sudan due to concerns it could damage Britain’s relationship with the United Arab Emirates, a leading war crimes investigator has told Parliament.

The Foreign, Commonwealth & Development Office (FCDO)’s atrocity prevention team received multiple warnings of “one of the single largest mass casualty events of the 21st Century”, before UAE-backed paramilitaries stormed the Sudanese city of El Fasher last October.

Nathaniel Raymond, executive director of the Humanitarian Research Lab (HRL) at the Yale School of Public Health, said his team provided UK officials at the FCDO with real-time intelligence over more than two years warning that the siege of the city would culminate in mass civilian killings.

But despite the warnings it failed to act, with officials citing political concern over the reaction of the UAE which was backing Sudan’s Rapid Support Forces (RSF), Mr Raymond told the International Development Committee, appointed by the House of Commons to scrutinise the work of the FCDO, on Tuesday.

Officials “prioritised HMG’s [His Majesty’s Government’s] economic, security, and diplomatic relationships with the UAE above preventing the intentional starvation, forced displacement, and the genocidal slaughter of tens of thousands of civilians living in El Fasher and its surrounding communities,” he told MPs in a written statement.

The UAE has been widely accused of smuggling arms to the RSF – something it has strenuously denied.

Last October, the RSF, which has been fighting a four-year civil war against government forces, captured the sprawling city of El Fasher in western Sudan after an 18-month siege that UN investigators concluded bore the “hallmarks of genocide”.

According to satellite imagery and open-source intelligence gathered by Mr Raymond’s team at Yale, at least 60,000 people may have been killed within weeks of the city’s fall.

The scale of the massacre is six times that of the 1994 Srebrenica Genocide in Bosnia, twenty times 9/11, and higher than the initial death toll after the 1945 atomic detonation in Nagasaki, Mr Raymond told MPs in a written statement.

In testimony submitted to MPs on Tuesday, Raymond said that, between mid 2023 until the fall of the city in October 2025, the UK government – the UN Security Council’s penholder or lead member on Sudan – had been given “more than sufficient” intelligence to develop policy options that could have prevented the catastrophe.

He said: “These options should have included the active application of public and private pressure by His Majesty’s Government (HMG). For example, direct sanctions against UAE officials, at minimum, could have been used to interdict the clandestine UAE pipeline of advanced weaponry flowing to the RSF.”

Instead, Mr Raymond alleges that ministers prioritised HMG’s economic, security, and diplomatic relationships with the UAE – with concerned UK officials telling him so directly.

“The failure across two successive UK administrations to stop the El Fasher massacre from occurring appears to be the result of a leadership commitment by HMG to place the strategic relationship with the UAE above the international legal obligations to prevent genocide,” he said.

Mr Raymond recalled a moment in May 2024, when FCDO officials asked him to publicly release evidence of intercepted mobile phone data linking the UAE to the RSF because Britain was facing “significant private pressure” from Abu Dhabi that limited its ability to respond politically.

“They told me that the UK was facing significant private pressure behind the scenes from the UAE limiting its ability to affect the situation,” he wrote in his statement.

He added: “The FCDO officials asked that I publicly release the phone data analysis linking UAE-based facilities to the RSF.

“In other words, HMG was asking a private research lab in an American university’s epidemiology department, not GCHQ or the SIS [Secret Intelligence Service], to provide support for efforts to confront the UAE for its covert support to the RSF”.

The inference is either that officials acted without ministerial approval or that ministers wanted the data out but did not want to be seen to be doing it themselves.

The FCDO’s approach to atrocity warnings and escalation was also questioned in meetings with officials described by Mr Raymond.

He said that at a meeting with FCDO officials in May 2024, civil society members were told that NGOs could only “warn once” about the imminent fall of El Fasher, or risk being seen as “crying wolf”.

He also said the FCDO took an overly literal reading of its obligations under UN Security Council Resolution 2736 – which demanded that the RSF immediately halt the siege of El Fasher – and refused to take additional measures against the RSF’s backers.

Both protected the FCDO politically by limiting the potential for public condemnation or action against the UAE.
Mr Raymond said that around the same period, RSF operations appeared to pause immediately following the passage of the resolution.

He said his team at Yale were told by a source with direct knowledge of RSF internal operations that Abu Dhabi had instructed RSF leader Muhammad Hamdan Dagalo Musa to pause the assault so the UAE could assess whether there would be political consequences.

But the FCDO missed the opportunity to act to deter the UAE – despite being told it had a window to do so, he said.

“In retrospect, I believe the most successful atrocity prevention step taken by HMG and the international community was when the UAE had a brief period of concern that UNSCR 2736 could include political consequences. Once Abu Dhabi assessed there would be no consequences, the attack resumed,” he told MPs.

“The tragedy of El Fasher shows that advanced technology and analysis can provide leaders essential decision support information, but satellite data and computing power cannot by itself generate either political will or moral courage”.

The period over which Mr Raymond’s criticism relates covers the end of the Sunak government and the start of the Starmer government.

The three relevant Foreign Secretaries were Lord David Cameron, David Lammy and Yvette Cooper.

The FCDO has been contacted for comment.

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