The owner of a Twitter account that appears to belong to former Trump aide George Papadopoulos has gone on a tirade about former Australian foreign minister Alexander Downer.

The tweets appear to be an attempt to undermine Mr Downer and portray him as an opponent of the Trump campaign.

What has Mr Downer got to do with any of this?

Papadopoulos first encountered Mr Downer in a London bar in May 2016, when Mr Downer was the Australian high commissioner to the UK.

He reportedly told Mr Downer that he knew Russia had damaging information about Hillary Clinton.

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The Australian Government then tipped off US intelligence services about the meeting.

The meeting appears to have sparked the probe into Russian interference in the election, which would eventually morph into special counsel Robert Mueller's investigation.

What was said about Mr Downer?

The account @georgepapa19 tweeted on Tuesday that Mr Downer is a "Clinton friend" who is "connected to the MI6, and private intelligence organizations in London".

It also said Mr Downer wanted to meet under "incredibly suspicious circumstances".

The tweets make unsubstantiated claims about Mr Downer's connection to then-British prime minister David Cameron, and says the two discussed Papadopoulos' connection to energy projects in Israel.

@georgepapa19 tweeted that Mr Downer was sent by "some organization to meet me", and Mr Downer's connections need to be investigated.

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Papadopoulos has said in multiple media interviews he does not remember telling Mr Downer anything about emails or Russian dirt on Ms Clinton.

The tweets also say Mr Downer needs to be "as exposed as Christoper (sic) Steele".

The ABC has contacted Mr Downer for comment.

Christopher Steele? Who's that?

Mr Steele is the former British spy who was commissioned to write the infamous Steele dossier, which made salacious claims about an alleged wild weekend US President Donald Trump had in Russia.

The use of Mr Steele and Ms Clinton's names in the tweets closely aligns with conspiracy theories spun by Mr Trump's defenders.

As to the veracity of the tweets, American cable news network MSNBC, Fairfax and Ten have reported the Twitter account belongs to Papadopoulos.

What's the point of going after Mr Downer?

The May 2016 meeting between Papadopoulos and Mr Downer is one of the most important moments in the entire Trump/Russia investigation.

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Casting doubt on Mr Downer and the reasons for the meeting has become the holy grail for Mr Trump's legal defence team.

If they can prove there was something dodgy about Mr Downer, they can potentially invalidate the entire investigation.

Trump-friendly Republican Congressmen and conservative commentators have attempted to draw a link between Mr Downer and Ms Clinton.

They say that a $25 million payment the Australian government paid to Bill and Hillary Clinton's charitable foundation in 2006 shows Mr Downer is in cahoots with the Clintons.

This connection has been dismissed by a spokesman for Ms Clinton as "pathetic".

Alexander Downer didn't mention the Twitter rant when accepting an honorary doctorate from the University of Adelaide on Tuesday. ( ABC TV )

What ended up happening to Papadopoulos?

Just last week, Papadopoulos was sentenced to 14 days in prison for lying to the FBI, which he has yet to serve.

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The account @georgepapa19 tweeted he regrets lying to the FBI, and he hopes they investigated his concerns he was being recorded by Mr Downer on his phone during their conversation.

Originally, Papadopoulos agreed to cooperate with investigators in exchange for leniency.

But that relationship eventually soured.

Mr Mueller's office said Papadopoulos had undermined the investigation and slowed them down.

They also said Papadopoulos and his wife had given multiple misleading interviews in the media.

Instead of asking for a lenient sentence, the special counsel recommended jail time.

Russia, If You're Listening is an ABC podcast about the investigation into Russia's interference in the US election. Find it in the Listen App, in Apple Podcasts or your favourite podcasting app.