President Trump has angrily denied claims that his former lawyer, Michael Cohen, is willing to testify that Mr Trump knew and approved of the 2016 meeting between his son Donald Jr. and Russian government officials.

The meeting saw the Trump campaign offered “very high level and sensitive information" as part of "Russia and its government’s support for Mr Trump”.

The president regularly insists he did not know of the meeting.

If true, this revelation would directly implicate Mr Trump himself in an effort to conspire with a foreign power to tip the election to him, and a subsequent cover-up effort.

US commentators are saying the importance of this story may not lie in what Cohen is willing to say about Trump’s alleged knowledge of this meeting.

Rather, the further unravelling of the Cohen-Trump relationship could lead Mr Cohen to share previously undisclosed information about other matters related to Mr Trump's relationship with Russia that are still shrouded in mystery.

Mr Cohen alleges that he was present, along with several others, when Mr Trump was informed of the Russians’ offer by Trump Jr.

White House may have edited out question where Putin says he wanted Trump to win 2016 US election

According to Mr Cohen’s account, it was Mr Trump who approved proceeding with the Russian meeting.

But it must be remembered that Mr Cohen is a disgruntled ex-employee of Mr Trump's. He may have a score to settle.

Mr Trump's present lawyer, Rudy Giuliani, says the version of events that are supposedly about to be put forward by Mr Cohen never happened.

The testimony of Mr Cohen could also prove useful in answering other areas of interest identified by Robert Mueller's inquiry.

Special Counsel Mueller allegedly has evidence that Mr Cohen secretly travelled to Prague in the summer of 2016 to discuss concealment strategies with Russian officials over the extent of his then-employer's links to Moscow.

Trump in Helsinki: Putin meeting and protests Show all 16 1 /16 Trump in Helsinki: Putin meeting and protests Trump in Helsinki: Putin meeting and protests President Trump meets with Russian President Vladimir Putin in Helsinki Reuters Trump in Helsinki: Putin meeting and protests An advert from Finnish newspaper Helsingin Sanomat is on display in Helsinki Reuters Trump in Helsinki: Putin meeting and protests President Trump in a meeting with Finnish President Sauli Niinisto AFP/Getty Trump in Helsinki: Putin meeting and protests President Trump meets with Finnish President Sauli Niinisto in Helsinki EPA Trump in Helsinki: Putin meeting and protests President Trump talks with Finnish President Sauli Niinisto in Mantyniemi, the official residence of the Finnish President EPA Trump in Helsinki: Putin meeting and protests US, Finnish and Russian flags fly in front of the Presidential Palace in Helsinki EPA Trump in Helsinki: Putin meeting and protests A protester wears a mask featuring a portrait of Russian President Vladimir Putin during the so-called "Helsinki against Trump and Putin" demonstration on July 16, 2018, in the Finnish capital Helsinki. The US and Russian leaders opened an historic summit in Helsinki on Monday, with Donald Trump promising an "extraordinary relationship" and Vladimir Putin saying it was high time to thrash out disputes around the world. / AFP PHOTO / Jonathan NACKSTRANDJONATHAN NACKSTRAND/AFP/Getty Images JONATHAN NACKSTRAND AFP/Getty Trump in Helsinki: Putin meeting and protests Vladimir Putin gifts a football to President Trump at the press conference that followed their meeting AP Trump in Helsinki: Putin meeting and protests Trump supporters hold banners during a demonstration in Helsinki AFP/Getty Trump in Helsinki: Putin meeting and protests People protest for women's reproductive rights in Helsinki's Senate Square Reuters Trump in Helsinki: Putin meeting and protests A crowd watches the motorcade transporting President Trump through Helsinki AFP/Getty Trump in Helsinki: Putin meeting and protests Russian President Putin drives through Helsinki on his way to meet with President Trump EPA Trump in Helsinki: Putin meeting and protests A man in the audience of the joint press conference holds up a sign sign that reads "NUCLEAR WEAPON BAN TREATY". REUTERS Trump in Helsinki: Putin meeting and protests A man is removed from the joint press conference in Helsinki. Security removed the man after he pulled out a sign that read "NUCLEAR WEAPON BAN TREATY". REUTERS Trump in Helsinki: Putin meeting and protests President Trump and Russia's President Putin sit for a working lunch in Finland's Presidential Palace AFP/Getty Trump in Helsinki: Putin meeting and protests President Trump meets with Russian President Vladimir Putin in Helsinki Reuters

Mr Cohen adamantly refutes this.

So far, no evidence has been publicly produced to prove that Mr Cohen's Prague meeting did actually happen.

“Cohen may have other things to say about the Trump-Russia connection beyond the Trump Tower meeting,” said Bob Bauer, the former White House counsel under President Barack Obama.

“What else does he know about the Trump campaign’s planning to extract maximum benefit from the Russians? This is just the opening salvo.”