Ever since Donald Trump won the US Presidential race, critics have speculated on the likelihood of his impeachment, suggesting his varied business interests or the tactics used during his election campaign could mean the country is on its way to another Watergate.

Parallels between Richard Nixon, the only President in US history to resign following the Watergate scandal and Mr Trump’s current controversy-hit tenure of the White House are easy enough to find. For one thing, Mr Trump’s apparent preoccupation with leaks recalls Nixon’s similar concerns.

The road to Watergate began early in the Nixon administration, just three months after his inauguration, when the President ordered his head of security, Henry Kissinger, to wiretap members of his own staff in an effort to stop embarrassing leaks of secret information.

Special Report: Watergate - the untold story Show all 4 1 /4 Special Report: Watergate - the untold story Special Report: Watergate - the untold story pg-32-watergate-1-reuters.jpg Former US President Richard Nixon gives his farewell speech at the White House after resigning on 9 August 1974 Reuters Special Report: Watergate - the untold story pg-32-watergate-2-ap.jpg Carl Bernstein (left) and Bob Woodward, who first exposed the Watergate scandal, at The Washington Post in 1973 AP Special Report: Watergate - the untold story pg-32-watergate-3-ap.jpg Jeb Magruder, an ex-Nixon aide, testifies at the Senate Watergate Committee in 1973 AP Special Report: Watergate - the untold story pg-32-watergate-4-corbis.jpg Nixon with chief of staff H R Haldeman Corbis

After the resignation of his head of security, Michael Flynn, Mr Trump tweeted: “The real story here is why are there so many illegal leaks coming out of Washington?”

Mr Flynn’s now notorious private conversations with Russian Ambassador Sergey Kislyak are not unprecedented in American history. Mr Kissinger met a KGB spy at the Soviet Union Embassy in Washington just 18 days before Nixon’s 1969 inauguration.

Just as Mr Trump has called for improved relations with Russia, in 1969 the Kremlin wanted a thawing of the Cold War. At his swearing-in, Nixon addressed Moscow directly, reassuring the Soviet Government: “Our lines of communication will be open”.

While there is no doubt Mr Kissinger was merely following orders, the White House has vehemently denied Mr Trump had any prior knowledge of Mr Flynn’s unauthorised dealings with the Russians – but the consequences of Mr Flynn’s off-script diplomacy could lead the US into unchartered waters.

It is widely expected that Mr Flynn will be subpoenaed to testify under oath. One of the two men with the power to issue him with a subpoena is Republican Senator John McCain, a Cold War era veteran who dislikes the idea of cosying up to President Putin. The other is FBI director James Comey.

The FBI has been looking into Mr Flynn’s dealings with Russia for some time and has said it believes Russian state-sponsored hacking was used to influence the outcome of the Presidential election last year.

Mr Flynn is believed to have accepted payments from Russian state-controlled news organisation the Russian Times and appeared as Mr Putin’s honoured guest at a televised banquet in 2015 - before he signed up to the Trump campaign.

Mr Flynn was a particularly vocal opponent of Hillary Clinton’s in the later stages of the campaign, continually tweeting unsubstantiated claims about her and chanting “Lock her up” at rallies.

After Mr Trump was sworn in, Mr Comey expressed fears that Mr Flynn could be susceptible to Russian blackmail, and took his concerns to his direct boss - Sally Yates, acting Attorney General of the US, who Mr Trump fired on January 30, just ten days after his inauguration.

When Mr Trump dismissed Ms Yates after she refused to defend his controversial travel ban, it was noted that the only other President to effectively dispense with his Attorney General was Richard Nixon in the so-called ‘Saturday night massacre’ which took place at the height of the Watergate scandal.

The FBI wants to know whether members of Trump's campaign team were in cahoots with the Russians to ensure their man ended up in the White House – and commentators believe the consequences of establishing such a link could be as dramatic as the fallout from Watergate.

Four current and former US officials told the New York Times that they had evidence of repeated communications between the Trump campaign team and Russian officials. They claim to have intercepted phone calls and other communications around the same time as Russia is believed to have carried out its “fake news” campaign against Ms Clinton.

The Watergate scandal centred on how much Nixon knew - and when - about the burglary of the Democratic headquarters and the role this played in his 1972 re-election, followed by a constitutional crisis between the judiciary and the President when Nixon refused to hand over secretly recorded conversations from the Oval Office.

Dan Rather, an American journalist who won acclaim for his coverage of Watergate as a White House correspondent, said: “On a 10 scale of Armageddon for our form of Government, I would put Watergate at a 9.

“This Russia scandal is currently somewhere around a 5 or 6, in my opinion, but it is cascading in intensity seemingly by the hour.”

Just as Mr Trump has gone to war with the media, threatening to sue numerous outlets and calling highly respected newspapers including the New York Times “fake news”, Nixon threatened the same newspaper with libel for a story about his Vice-Presidential running mate, Spiro Agnew.

Mr Agnew would repeatedly call out individual reporters by their name in speeches angrily denouncing the media, just as Mr Trump has started arguments with individual journalists and repeatedly sent out tweets attacking "fake news".