Special counsel Robert Mueller’s final report into Russian interference in the 2016 US election may never been seen in public, despite a drip feed of tantalising details being published over the last week.

As key aides to Donald Trump prepare to be sentenced this week for crimes relating to the Russia inquiry, the president's lawyers are pouring over little-known rules that dictate how the long-awaited conclusion of the probe is handled.

On Friday, intrigue over the protracted investigation, which opponents hope could open the door to impeachment for collusion with Russia in the 2016 elections, was fuelled by Mr Mueller publishing key guidelines for sentencing suspects.

Mr Mueller's team announced that Michael Cohen, the former personal lawyer for Donald Trump due in court on Wednesday, had met a Russian promising “political synergy” with the Trump election campaign, and even offering a meeting with Vladimir Putin.

Mr Mueller also announced that Paul Manafort, Mr Trump’s former campaign manager, told prosecutors "multiple discernible lies" about his contacts with Russians. Mr Trump, in the early hours of yesterday (SAT), insisted that the documents proved he played no role in Russian inteference.