Donald Trump, the US president, has called for former FBI director James Comey to be jailed, accusing him of revealing classified information and of lying to Congress.

In addition to suggesting the former intelligence chief be incarcerated, Mr Trump called him "slippery" and a "slimeball" and said he would go down as the worst FBI director in history, during a Twitter rant which spanned the course of two hours on Sunday morning.

He also challenged accusations made by the former FBI director in a tell-all book that is due for release this week.

Mr Trump wrote: "The big questions in Comey’s badly reviewed book aren’t answered like, how come he gave up Classified Information (jail), why did he lie to Congress (jail), why did the DNC refuse to give Server to the FBI (why didn’t they TAKE it), why the phony memos, McCabe’s $700,000 & more?"

He added: "I never asked Comey for Personal Loyalty. I hardly even knew this guy. Just another of his many lies. His “memos” are self serving and FAKE!"