William Webster, the only man to head both the FBI and the CIA, has urged the US Senate to reject Kash Patel and Tulsi Gabbard, Donald Trump’s nominees as directors of the bureau and national intelligence, arguing that they are unqualified.

Writing to senators, Webster, who is aged 100 and who was appointed by both Democrat and Republican presidents, called on them to “weigh the critical importance of nonpartisan leadership and experience” and suggested that Patel and Gabbard possessed neither attribute.

“The safety of the American people – and your own families – depends on it,” he wrote, emphasising the importance of Senate confirmation hearings that will scrutinise the two nominees.

Wesbster, who was appointed as FBI director by Jimmy Carter in 1978, took aim at Patel’s suitability to head the bureau, implying that he exhibited an over-zealous loyalty to Trump that could undermine the rule of law and set a “dangerous precedent”.