In one May 2016 email highlighted in the report, John S. Flynn, a senior advisor to the vice president sent Joe a schedule for his call with then-Ukrainian president Petro Poroshenko – and copied Hunter in the message.

Hunter was on the board of Ukrainian gas company Burisma at the time.

'Boss–8.45am prep for 9am call with Pres Poroshenko. Then we're off to Rhode Island,' the email said, and attached a Microsoft Word document with a briefing.

Marco Polo claims that copying Hunter in the VP's schedule constitutes a use of nonpublic information from a government job for financial gain, which allegedly violates section 2635 of the US Code of Federal Regulations.

Flynn sent the message to an alias email address Joe used under the name 'Robert Peters'.