Disclaimer: This is just a theory based on the timing of his first appearance and the current state of the Marvel Cinematic Universe (MCU)
To understand this theory, we have to look at the specific time the movie is going to most likely be set in. Because of the way the MCU works (with all the shows and movies interconnected), every installment set in present day usually occur around the time they are theatrically released. So [Captain America: Civil War](tag:994409) will probably take place around May 2016.
Why is that important? Well, depending on when it exactly takes place, it could and probably will be right before elections. The current president of the MCU is Matthew Ellis, who you may remember being held hostage in Iron Man 3, or in television broadcasts elsewhere in the universe. Depending on how long he has been president, he may have even already served his maximum 8 years.
So with both the events of [The Avengers: Age Of Ultron](tag:293035) and the sudden influx of Inhumans on the mind of the American people, it would make sense that presidential hopefuls will be attempting to pander to those who are afraid of "Powered" people.
And I think this is where Martin Freeman's character comes in. My theory is that he is a senator or other government official who is running for president, and is leading the charge on the "Sokovia Accords" in an attempt to put himself in the Whitehouse.
And although no one knows if he signed a contract to appear in future movies, he seems to be a relatively liked actor and I am sure alot of people would love to see him stick around. If he does end up becoming president, it would be a good but minor role that would allow him to keep coming back no matter how busy he is.
What do you think? Give me your opinion in the comments below!