Mayor Boris Johnson has confirmed talks for a London NFL team are "underway".
The capital has hosted NFL matches the last six years since Wembley Stadium reopened, and tickets for October's encounter between the Jacksonville Jaguars and the San Francisco 49ers sold out five months ago.
The Minnesota Vikings will also face the Pittsburgh Steelers a month before the Jaguars play the 49ers, as the sport's popularity grows in the UK.
Asked whether he would still back the NFL bringing a team to Britain permanently, Johnson enthusiastically replied: "Very interested in NFL - talks underway!"
Jacksonville Jaguars owner Shahid Khan last week negotiated the takeover of Barclays Premier League club Fulham for a sum between £150-200 million.
Feasibly, Khan could rebrand the Jaguars as a British-based side due to their poor attendances.
A London NFL team would host eight matches on home soil - most likely at the London 2012 Olympic stadium - and travel to the States for eight away games.
Uncertainty, however, stems from the now defunct NFL Europe, backed by the NFL between 1991 and 2007.
The league underwent a number of rebrandings but failed to thrive on the continent.