Antigua's Prime Minister Lester Bird, has conceded defeat in a general election which took place on Tuesday.
Bird denied scandals had decided the election
It marks the end of a political dynasty which has dominated Antigua and Barbuda since the 1950s.
Excited islanders took to the streets as preliminary results showed a win for opposition leader Baldwin Spencer.
Mr Spencer is a lifetime labour activist who has promised to end the corruption endemic in the eastern
Mr Spencer had told the BBC's Caribbean Service that despite a series of scandals, successive Antigua Labour Party governments had done nothing to prevent corruption.
The new prime minister repeated his pledge to stamp out corruption early on Wednesday, after Mr Bird conceded that preliminary results showed the opposition United Progressive Party had "won overwhelmingly".
"Yesterday, the soldiers of the people's crusade delivered the only judgment fit for the Antigua Labor Party's crimes against the people of Antigua and Barbuda," he said.
"Crimes committed against the people must be punished. We will let the chips fall the way they may."
The outcome became clear after the opposition won three out of the first four seats in the lower house, known as the House of Representatives.
The Electoral Commission is expected to issue the final results later on Wednesday.
Long running reign
Mr Bird denied his defeat was linked to allegations of corruption against him.
In an earlier interview with the BBC's Caribbean Service Mr Bird said that his party had laid down strict anti-corruption guidelines, following a 2002 inquiry into the national medical insurance scheme that led to fraud charges against seven officials.
Mr Bird said the people had just wanted a change.
"Elections were not contested on issues but on the basis of a time for change," he said.
The governing ALP had been seeking a seventh term in office.
Politics in the twin-island nation have been dominated by the Bird family for more than half a century - the family has held the post of prime minister since independence from Britain in 1981.
Mr Bird has been prime minister of Antigua and Barbuda since 1994, when he took over from his father Vere.