DONALD Trump is said to be still holding out hope that he can persuade retired vice admiral Robert Harward to change his mind and take on the key role of his National Security Adviser.

The US President suffered another serious blow after the former Navy SEAL turned down the offer to serve. Mr Harward insisted his decision had been a purely personal one. “I'm in a unique position finally after being in the military for 40 years to enjoy some personal time," he explained.

The retired vice admiral has widespread experience and was described by Mr Trump as an “outstanding” candidate ahead of his refusal.

The 60-year-old served as deputy commander of US Central Command under James Mattis, who is now the Defence Secretary. He also served on the National Security Council under President George W Bush and commissioned the National Counter Terrorism Centre.

He is currently based in Abu Dhabi as an executive for Lockheed Martin, the US defence contractor.

In the wake of the resignation of Michael Flynn - who quit at Mr Trump's request on Monday after revelations that he had misled Vice President Mike Pence about discussing sanctions with Russia's ambassador to the US during the transition - the President has now suffered another embarrassing setback.

However, Mr Trump is said to be privately trying to change Mr Harward’s mind, inviting him back to the White House for talks. One source said the retired vice admiral was “conflicted” between the call to serve the US administration and its “dysfunctionality” under the current presidency.

If Mr Trump’s powers of persuasion fail, then there could be two other potential contenders in the running for the job: Keith Kellogg, the acting National Security Adviser, and David Petraeus.

Mr Kellogg, a retired three-star general, was named as the acting National Security Adviser after Mr Flynn stepped down.

The 72-year-old has had a long career in the US Army, serving in Vietnam and Iraq, before retiring in 2003 and becoming a security consultant for Oracle, the software giant.

Mr Petraeus, also a retired general, resigned as CIA director in 2012 and pleaded guilty to a charge of mishandling classified information relating to documents he had provided to his biographer, with whom he was having an affair. He was also fined £80,000 and remains on probation.

However, if either Mr Kellogg or Mr Petraeus is given the job, it will be in the knowledge they will be the President’s third choice.

At an extraordinary press conference, Mr Trump insisted his government was running like a "fine-tuned machine" and again lashed out at America's news media for being "out of control".

He denounced broadcasters and the press for peddling fake news and vowed to bypass them to take his message "straight to the people".

Addressing the press, the President declared: “The public doesn't believe you people any more. Now, maybe I had something to do with that. I don't know. But they don't believe you.

"But you've got to be at least a little bit fair and that's why the public sees it. They see it. They see it's not fair. You take a look at some of your shows and you see the bias and the hatred."

Nearly a month into his presidency, Mr Trump said his new government had made "significant progress" and took credit for an optimistic business climate and a rising stock market.

He pushed back against widespread reports of a chaotic start to his administration marked by a contentious executive order - now tied up in a legal fight - to place a ban on travellers from seven predominantly Muslim nations.

On Monday, the focus will be on the Commons as MPs debate the President’s forthcoming state visit to Britain following a petition calling for it to be downgraded topped 1.8 million signatures.

Speculation is rife that Whitehall and Buckingham Palace are trying to minimise disruption as much as possible by organising events during the summer parliamentary recess and outwith London as much as possible. A visit to Scotland for Mr Trump, possibly to Balmoral, is said to be a “no-brainer” given his family and business links.

But the Stop Trump campaign has pledged to hold the largest demonstration in history wherever the President travels to.