In a surprise result which could herald an early Israeli general election Amir Peretz has ousted Shimon Peres as leader of the Labour party. The union chief has vowed to pull his party out of Prime Minister Ariel Sharon’s ruling coalition.Polls had predicted Perez would easily win the leadership contest. In the end he was narrowly defeated – 42 per cent to 40. The veteran politician took Labour into Sharon’s government last year as a junior partner to help carry out Israel’s withdrawal from Gaza and parts of the West Bank. The outcome will fuel growing doubts about the coalition’s viability after it was undermined by hardliners in Sharon’s Likud party angered by the Gaza pullout. Peres had indicated he would keep Labour within the government if he won.