“There’s no incentive to investigate if the president and the White House themselves have announced that aid is unconditional,” said Brian Finucane, who worked for a decade in the Office of the Legal Adviser at the State Department advising on arms transfers and the laws of war.

“That means they don’t want to hear inconvenient legal conclusions,” he told The Independent.

Mr Finucane said senior administration officials he had spoken to had been met with a “shrug” by the US intelligence community when they quizzed them about mass civilian casualty incidents caused by Israeli bombing, “because it’s no one’s job in the US intelligence community, apparently, to actually investigate these things.”