Hours after US President Donald Trump announced that he had ordered the Department of Justice to launch a "complete review" of leaks of the UK investigation into the Manchester Arena bombing by US intelligence agencies, British officials say the close working relationship has resumed.
"Having received fresh assurances, we are now working closely with our key partners," Mark Rowley, assistant commissioner for the Metropolitan Police Service, told the BBC.
Trump's statement came after public criticism from UK ministers and police of a series of damaging leaks said to have caused "distress" to families of victims.
The president connected the leaks on the Manchester bombing to other recent leaks from US intelligence – often about the FBI's investigation into the Trump campaign's alleged Russian connections – about which he has often publicly complained.
"The alleged leaks coming out of government agencies are deeply troubling. These leaks have been going on for a long time and my administration will get to the bottom of this," he said. "The leaks of sensitive information pose a grave threat to our national security.
"I am asking the Department of Justice and other relevant agencies to launch a complete review of this matter, and if appropriate, the culprit should be prosecuted to the fullest extent of the law.
"There is no relationship we cherish more than the special relationship between the United States and the United Kingdom."
Earlier in the day, UK prime minister Theresa May took the highly unusual step of announcing publicly that she would be warning Trump that information shared with the US must be "secure".
In a short statement on Thursday before she travelled to a NATO summit, May said the UK's threat level remained at critical, and that she would be discussing terrorism with other national leaders at the meeting of the defence alliance.
"Shortly I will be travelling to a NATO summit where I will be working with international colleagues on defeating terrorism," she said. "I will make clear to President Trump that intelligence that is shared between our law enforcement agencies must remain secure."
UK police and security services have expressed anger and frustration at a series of detailed leaks of information relating to the ongoing investigation into the Manchester bomber Salman Abedi and his possible associates. Eight people have been arrested so far and remain in custody.
US intelligence figures have leaked information, including the name of the bomber – while police were still asking media to keep this confidential – as well as details of his possible routes, his history, and even detailed photographs and information from the scene of the bombing. Officers say this has risked compromising the investigation.
On Thursday morning, the BBC reported that Greater Manchester police had suspended information sharing on the incident with US law enforcement. UK and US law enforcement and intelligence agencies enjoy a close relationship, usually routinely sharing a great deal of information on major investigations in real-time.
Ian Hopkins, chief constable of Greater Manchester police, said on Thursday that the US leaks to the media were also causing distress to the families of the victims. He referred specifically to a New York Times story that included police photographs from the scene, including remnants of the backpack and detonator used by Abedi.
"We have a team of specially trained officers who have been supporting the families of those who tragically lost their lives," said Hopkins. "Last night the family liaison officers shared with them the fact that intelligence had been leaked and published in the New York Times. It is absolutely understandable that this has caused much distress for families that are already suffering terribly with their loss.
"A statement was issued by the National Counter Terrorism Police Network last night. I do not wish to add anything further to this and I will not be commenting on information sharing arrangements with our international partners. "
The statement referred to by Hopkins was released on Wednesday evening, and warned that the continued leaks threatened damaging the trusted relationship between the US and UK.
“When that trust is breached it undermines these relationships, and undermines our investigations and the confidence of victims, witnesses and their families," it said. "This damage is even greater when it involves unauthorised disclosure of potential evidence in the middle of a major counter terrorism investigation.”
Even a rare public rebuke from home secretary Amber Rudd on Wednesday morning did little to stem the flow of information from the US.
"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," she told the BBC's Today programme.
UK and US intelligence agencies each have staff based in the headquarters of the other countries, while the signals intelligence agencies GCHQ and NSA work side-by-side in sites across the world as part of the Five Eyes intelligence network.
One UK intelligence source told BuzzFeed News the leaks caused both actual and reputational damage, "because it gives as-yet-unidentified targets in the network a heads-up on the investigation, and also if the victims families are hearing the target's name etc from CBS it makes the UK look shit!"
Another frustrated source remarked: “It’s Five Eyes – and one big mouth.”
Senior figures are keen to flag their displeasure and bolster efforts from senior US intelligence official to stem the flow of leaks, but also trying to reiterate their desire to keep the broader intelligence relationship close and friendly – efforts that have proved a running theme in the difficult early days of the "special relationship" under the Trump presidency.
Shashank Joshi, an analyst at the security think tank RUSI, who was one of the first to note the strains caused by the series of US leaks on Manchester, said there was a risk of long-term strains to the UK-US intelligence relationship if the issue is not addressed.
"The bulk of what has been leaked is not very operationally damaging, but I think we're fast approaching the point where UK officials might start being much more careful with what information they share," he said.
"This is worrying, as it means that it'll be harder to draw on American resources and fund patterns. I also wonder if information will be shared more selectively, for instance, with the NSA, which is presumably more disciplined, but more sparingly with law enforcement bodies."
In a blog post, Chris Webb, a former head of news at Scotland Yard, said the intelligence-sharing relationships were crucial and that steps must be taken soon to address the leaks.
"The sharing of intelligence with overseas law enforcement agencies is normal practice," he wrote. "When something like 7/7 or Manchester occurs it is important that information and photographs are shared so that all those involved in the fight against terrorism understand the latest techniques being adopted and applied by the terrorists.
"However for one of those agencies to give confidential information to a news organisation is a disgrace. Intelligence, trust and confidence come together in tackling terrorism. By leaking information to the New York Times and others, the American intelligence service has damaged that significantly.
"I fervently hope that the UK authorities get the assurances they need swiftly – that means hours or days – that such leaks will not happen again. Ultimately, we cannot afford NOT to share information with our partners and the Americans in particular. They have a massive global counter-terrorism operation; they are plugged, literally and metaphorically, into places and people that we are not."