The US President-elect's speech to hundreds of thousands of supporters in Chicago on Tuesday was one of the most widely-watched and repeated political addresses in recent history.
It was also partly written in a flat in Notting Hill, West London.
Parts of the speech were crafted by Jacob Rigg, a volunteer advisor to the Obama campaign.
Mr Rigg works for The Society of Trust and Estate Practitioners, which lobbies and advises on tax issues, including the rules that apply to non-domiciled foreigners living in the UK.
He also helped run Chris Huhne's campaign for the Liberal Democrat leadership last year.
Having worked in Washington as a lobbyist, Mr Rigg has links with some of Mr Obama's Senate staff, and remained in contact with the campaign this year.
Working from home in his own time, Mr Rigg was involved in writing the president-elect's speech, contributing by via phone, email and video conferences.
Mr Rigg said the inspiration for the Chicago speech was the most celebrated piece of oratory in American history, Abraham Lincoln's 1863 address at Gettysburg.
Lincoln's speech, made two years before the end of the American Civil War, spoke of the "unfinished work" and the "great task remaining" of building a democratic republic.
In his speech, Mr Obama said: "The road ahead will be long. Our climb will be steep. We may not get there in one year or even one term, but America - I have never been more hopeful than I am tonight that we will get there. I promise you - we as a people will get there."
Mr Rigg said: "The idea was a Gettysburg style of speech, talking about how what we have done is not enough, that this is not in itself enough."
Part of a much larger team working on the speech, some of Mr Rigg's writing appeared unchanged on Tuesday.
His contributions include Mr Obama's declaration that his election was "the answer that led those who have been told for so long by so many to be cynical, and fearful, and doubtful of what we can achieve to put their hands on the arc of history and bend it once more toward the hope of a better day".
Mr Rigg said also drafted a significant speech the world will never hear, the one that Mr Obama would have given if he had lost the election.
Mr Rigg gave few details of the concession speech, but said it would have had many similarities to the one Mr Obama gave after winning.
"It would have had a different emphasis, obviously, but it would still have tried to talk about trying but not succeeding, about how the journey itself is important."
Despite his close contacts with the Obama team, Mr Rigg said he had no plan to move to Washington to work with the new administration. "I quite like living in London really," he said
Instead, Mr Rigg is now looking for investors to help him set up his own consultancy advising charities and development groups on how to lobby governments - including the new US administration.