The party's acting leader, Harriet Harman, offered support for the vote in a commentary in the Sunday Times a U-turn on Labour's previous stance. The decision removes a potential obstacle to the referendum, which will be held by the end of 2017.
Prime Minister David Cameron of the Conservatives campaigned hard for the vote, making it a key policy during the May general election. Cameron won a majority in Parliament and Harman says it's now clear people want a chance to have their say.
