London ? British Prime Minister Gordon Brown made a dramatic bid to keep his beleaguered Labour Party in power after it was punished in elections last week, announcing he will resign by September at the latest even if the Liberal Democrats — being wooed by the Conservatives — decide to join his party in government.

The political theater, played out in front of the iconic black door of No. 10 Downing Street, comes as David Cameron’s Conservatives — which won the most seats in Parliament but fell short of a majority — struggled in their attempts to win over the third-place Liberal Democrats.

Brown’s party has been willing to entertain supporting the Liberal Democrats’ demand for an overhaul of the voting system toward proportional representation, which would greatly increase that party’s future seat tallies. But the evening brought a further twist with a counteroffer from the Conservatives — a referendum on a less dramatic type of electoral reform.