Donald Trump is more dangerous than Richard Nixon, says Watergate lawyer John Dean

Donald Trump’s unpredictability makes him more dangerous than Richard Nixon, according to the former White House attorney who helped in the Watergate cover-up before co-operating with investigators against the only president to resign from office.

John Dean said the probe by special counsel Robert Mueller into the current administration could end up being more damaging to the US than the scandal that brought down Nixon in 1974.

Mr Dean’s central role in the cover-up that brought down a president gives him a unique insight into the pressure mounting on the White House and parallels that span the decades.

He told The Telegraph that the Nixon he knew was "an authoritarian personality" just like Mr Trump appeared to be. But there were important differences, mainly that Mr Nixon understood the presidency better.

“They're very different in their perception of the president's authority,” he said. “Trump is more dangerous because he doesn't know what he's doing. The danger is he could do anything.

“If Mueller wants him, Trump could just say come and get me I have the Defence Department surrounding the White House. Then you've got a real problem.”

In Fire and Fury, author Michael Wolff's recently published expose of the Trump White House, Mr Trump was said to be a “John Dean freak”, comparing him with James Comey, whom Mr Trump fired as head of the FBI.

“Comey was a rat," said Mr Trump, according to the book. He then added: “John Dean. John Dean. Do you know what John Dean did to Nixon?”

Mr Dean, now 79, said he was pleased to be the focus of Mr Trump's ire.

He said: “It means that maybe somebody's reminding him that everything he's doing may be worse than Watergate, that maybe he's thinking about it.”

Mr Nixon was competent but dishonest, while Mr Trump appeared to be incompetent and dishonest, he added.

The Mueller investigation is looking into whether the Trump campaign colluded with Russian interference in the 2016 election.

Mr Dean said there were similarities in that Watergate began with a break-in at the headquarters of the Democratic National Committee, while "Russiagate" started with a hack of the DNC's computers. In both cases a special counsel was brought in and there were signs of a White House cover-up.

It was surprising how little the current administration appeared to have learned from the past in how to handle a special counsel investigation.

"There are lots of echoes of Watergate," he said.

Just as Nixon’s White House bungled the cover-up, so too Mr Trump should not have fired Mr Comey from the FBI.

“The firing of Comey by Trump was a terrific blunder, about as ham-handed as you can get, and not dissimilar from Nixon asking the CIA to block the FBI investigation into the Watergate break-in,” he said.

He added that current White House aides would be under intense pressure to co-operate with Mr Mueller.

“They've signed non-disclosure agreements but if they're in front of a grand jury and they lie - or they lie to the FBI - we've already seen what happens with Michael Flynn,” he said referring to the former national security adviser who was fired last year and has since pleaded guilty to making false statements.

Mr Dean, who after Watergate became an investment banker and author in Los Angeles, said Mr Trump should not expect an end to the Mueller investigation soon. It was more than two years from the Watergate burglary in June 1972 to Mr Nixon's resignation in August 1974.

“Today with social media it's everywhere and it seems to be going faster,” he said. “But the investigation may not be. You can only investigate at a certain speed. People can only talk (to Mr Mueller) at a certain speed.”