Flynn’s decision to work with Mr Mueller’s investigation in turn for leniency comes after reports his son Michael Flynn Jr, was being looked into.

There were reports Flynn was facing paying more than a million dollars in legal fees if he did not co-operate and would even have to put his house on sale.

In a statement Flynn said: “After over 33 years of military service to our country, including nearly five years in combat away from my family, and then my decision to continue to serve the United States, it has been extraordinarily painful to endure these many months of false accusations of 'treason' and other outrageous acts.

"Such false accusations are contrary to everything I have ever done and stood for. But I recognize that the actions I acknowledged in court today were wrong, and, through my faith in God, I am working to set things right. My guilty plea and agreement to cooperate with the Special Counsel's Office reflect a decision I made in the best interests of my family and of our country. I accept full responsibility for my actions."

Ty Cobb, the White House lawyer, said: “Today, Michael Flynn, a former National Security Advisor at the White House for 25 days during the Trump Administration, and a former Obama administration official, entered a guilty plea to a single count of making a false statement to the FBI.

“The false statements involved mirror the false statements to White House officials which resulted in his resignation in February of this year. Nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn.

"The conclusion of this phase of the Special Counsel's work demonstrates again that the Special Counsel is moving with all deliberate speed and clears the way for a prompt and reasonable conclusion.”

US stock markets took an initial hit after the news, with the Dow Jones dropping 1.4 per cent and the S&P 500 falling 1.6 per cent before rallying later.

James Comey, the former FBI director fired by Mr Trump, reacted by quoting the Bible in a tweet: “But justice roll down like waters and righteousness like an ever-flowing stream."