Sport England chairman Derek Mapp has quit after the government announced changes to the organisation's role.
Mapp claimed he was forced to quit. "I am deeply unhappy. I was willing to continue to deliver the new agenda but that was not deemed acceptable."
The job of getting the nation active has been taken from Sport England and handed to the Department of Health.
Sport England will now focus on increasing sports participation, mainly but not exclusively through clubs.
Mapp had advised James Purnell, the Secretary of State for Culture, Media and Sport, to be cautious about pushing through the changes as he was concerned some organisations would be left without any funding.
He said this was wrongly viewed as him being opposed to the new agenda.
Mapp, who was appointed just over a year ago, added: "Politics is a dirty old game sometimes and I'm a businessman trying to do my best, not a politician."
His resignation was accepted by Purnell, and a statement from the DCMS said: "Sport England will continue to play a major role in meeting the government's target of getting two million more people active by 2012."