Leaked intelligence about the Manchester bomb attack to the US media “undermines” the UK investigation, counter-terrorism officers said.
The National Police Chiefs’ Council has spoken out after photographs apparently showing bloodstained fragments from the concert bomb were published in the New York Times.
The pictures appeared a day after the bomber’s name was briefed to the US media against the wishes of Greater Manchester Police, and just hours after Home Secretary Amber Rudd issued a plea to US authorities not to leak material about the atrocity.
A National Counter Terrorism Policing spokesman said: “We greatly value the important relationships we have with our trusted intelligence, law enforcement and security partners around the world.
“These relationships enable us to collaborate and share privileged and sensitive information that allows us to defeat terrorism and protect the public at home and abroad.
“When that trust is breached it undermines these relationships, and undermines our investigations and the confidence of victims, witnesses and their families.
“This damage is even greater when it involves unauthorised disclosure of potential evidence in the middle of a major counter-terrorism investigation.”
Theresa May is expected to raise UK concerns when she meets Donald Trump on Thursday and British ministers have voiced their anger to American counterparts.
The disclosure is regarded as “completely unacceptable” by Britain, both because of the distress it may cause families of those killed or injured and because of the risk it could complicate ongoing investigations.
The row – which goes to the heart of the close intelligence-sharing relationship between the transatlantic allies – provides an awkward backdrop to the Prime Minister’s meeting with President Trump at the Nato summit in Brussels.
A Whitehall source said: “We are furious. This is completely unacceptable.
“These images leaked from inside the US system will be distressing for victims, their families and the wider public.
“The issue is being raised at every relevant level by the British authorities with their US counterparts.”
Rudd said on Wednesday morning she was “irritated” by the early release of Salman Abedi’s name and had made “very clear” to American counterparts that no further leaks should happen.
The Home Office declined to respond to the new leak, but pointed reporters to Rudd’s earlier comments in a clear indication that her stance had not changed.
A Downing Street spokesman made no comment.
The new pictures show torn scraps from a blue Karrimor rucksack as well as screws and nuts used as shrapnel and a metal item which the newspaper suggests could have been part of the bomb’s detonator.
The NYT described them as “law enforcement images”.
The nature of the photographs – one of which includes a ruler placed alongside the detonator – allowed no doubt that they were taken as part of the forensic investigation of the scene.
The paper also published a map showing the location of the victims of the bombing, positioned in a circle around the site of the explosion in the arena foyer.
The Home Secretary said she did not believe that the Americans had compromised the investigation.
But she added: “Quite frankly, the British police have been very clear that they want to control the flow of information in order to protect operational integrity, the element of surprise, so it is irritating if it gets released from other sources and I have been very clear with our friends that that should not happen again.”
Congressman Adam Schiff, a senior member of the House Intelligence Committee, said: “If we gave up information that has interfered in any way with their investigation because it tipped off people in Britain – perhaps associates of this person that we identified as the bomber – then that’s a real problem and they have every right to be furious.”
Manchester mayor Andy Burnham said he was “troubled” by the US leaks and had raised a complaint with the American ambassador to the UK.
“On Monday evening when the reports were first coming through to me, I agreed with the chief constable and others we would take a cautious approach to putting public information out, because we wouldn’t want to get anything wrong or compromise the police investigation,” Burnham told BBC2’s Newsnight.
“And yet the first reports were coming seemingly out of the United States. That is concerning because obviously you want international co-operation when it comes to sharing of information – because events like this can have that broader dimension – but it worries me greatly.
“And in fact I made known my concerns about it to the US ambassador.
“It’s not acceptable to me that here there is a live investigation taking place, we cannot have information being put in the public domain that’s not in the direct control of the British police and security services.”