In his first reaction Mr Trump said: "It's complete exoneration. No collusion, no obstruction."

The president said it was "a shame" that the country and his presidency had to go through the investigation and called it an "illegal take down that failed".

Mr Trump also appeared to call for an investigation into the Mueller probe itself and how it began.

Sarah Sanders, the White House press secretary, said: “The findings of the Department of Justice are a total and complete exoneration of the President of the United States.”

Robert Mueller spent 22 months investigation allegations of collusion between Donald Trump's presidential campaign and Russia credit: Tasos Katopodis/Getty Images North America

Lindsey Graham, the Republican senator close to Mr Trump, tweeted: “Good day for the rule of law. Great day for President Trump and his team.

“No collusion and no obstruction. The cloud hanging over President Trump has been removed by this report.”

However Democrats are demanding that Mr Mueller’s full confidential report be published and that all the underlying documents be handed to Congress so they can be reviewed.

The topline findings from Mr Mueller’s report were contained in a four-page summary written by William Barr, the US attorney general.

The summary was submitted to senior congressmen and released to the public on Sunday afternoon, giving the first insight into what Mr Mueller had concluded.

Democrats have demanded that William Barr, the US attorney general, release the report in full credit: Alex Wroblewski/Bloomberg

In the summary, Mr Mueller is quoted saying: “[T]he investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities."

Elsewhere Mr Mueller is quoted saying: "The evidence does not establish that the President was involved in an underlying crime related to Russian election interference".

That finding was effectively a victory for the US president, who has been saying constantly during the two years since he entered the White House that there had been “no collusion”.

As well as clearing Mr Trump and his campaign of conspiring with the Kremlin, Mr Mueller’s report also dealt with the allegations that the US president had obstructed justice by hampering the investigation.

Mr Barr's four-page summary of the Mueller report credit: Reuters

Mr Mueller did not reach a decision on whether Mr Trump had obstructed justice - meaning it was not a total victory for the president - instead deciding not to come to a conclusion.

Mr Barr’s summary cites Mr Mueller referencing “difficult issues” of law and fact - a likely nod to Department of Justice guidelines that say a sitting president cannot be indicted.

The summary of the report quotes Mr Mueller saying of obstruction of justice: “While this report does not conclude that the President committed a crime, it also does not exonerate him".

Given Mr Mueller decided not to make a decision on obstruction of justice but instead just hand over evidence, the Justice Department's leaders was left to made a determination.

Mr Barr and Rod Rosenstein, the deputy attorney general, decided there was not enough evidence to conclude that Mr Trump had acted with “corrupt intent”, and therefore decided he had not obstructed justice.

The summary did make passing reference to evidence of potential obstruction of justice by Mr Trump that has not yet featured in public reporting and which Mr Mueller looked at, but gave no more details.

The findings left the president and his allies delighted.

Mr Trump said: “It was a complete and total exoneration. It's a shame that our country had to go through this. To be honest, it's a shame that your president has had to go through this.”

The president also hinted that he wants somebody - possibly Republicans in Congress - to investigate the Mueller probe itself, which he believes should never have been created.

“This was an illegal take down that failed. And hopefully, somebody is going to be looking at the other side,” Mr Trump said.

Kellyanne Conway, a counselor to Mr Trump, said in a public message to the president: “Today you won the 2016 election all over again. And got a gift for the 2020 election.”

Democrats found themselves in a politically uncomfortable position, being asked during TV interviews whether they agreed there was no collusion and whether they trusted Mr Mueller - a man whose integrity they had repeatedly trumpeted in public.

Nancy Pelosi, left, and Chuck Schumer - the most senior Democrats in the House of Representatives and Senate credit: Aaron P. Bernstein/Getty Images

Nancy Pelosi and Chuck Schumer, the two most senior Democrats in the House of Representatives and Senate respectively, demanded the full report be published.

“Attorney general Barr’s letter raises as many questions as it answers,” the pair said in a joint statement.

“The fact that special counsel Mueller’s report does not exonerate the president on a charge as serious as obstruction of justice demonstrates how urgent it is that the full report and underlying documentation be made public without any further delay.

“Given Mr Barr’s public record of bias against the special counsel’s inquiry, he is not a neutral observer and is not in a position to make objective determinations about the report.”

Mr Barr said in his summary letter that he planned to release parts of Mr Mueller’s report, but it remains to be seen how much will be made public.

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