Former FBI Director James Comey says Donald Trump demanded personal loyalty to him (Zach Gibson/Getty Images)

Former FBI Director James Comey is due to give evidence to the Senate Intelligence Committee about conversations he had with President Donald Trump and whether the former businessman pressured him to drop an investigation into former National Security Advisor Michael Flynn.

The committee has already released his prepared opening statement in which he will confirm under oath that Mr Trump tried to get him to drop the probe into whether General Flynn, who was forced to resign two weeks after the inauguration, had met with Russian officials during the campaign to discuss economic sanctions imposed by Barack Obama.

He will also testify about a pair of phone calls with Mr Trump where he had reportedly complained to him about the FBI's investigation into his campaign team's links with Russia, calling it a "cloud" looming over the presidency and reportedly urged mr comey to state publicly that the President himself was not under investigation.