The final day of campaigning is taking place in Turkey ahead of a referendum on whether to grant sweeping new powers to the president. <br />President Recep Tayyip Erdogan is seeking to replace the parliamentary system with an executive presidency. <br />Approval could see him stay in office until 2029. <br />Supporters say a "yes" vote would streamline and modernise the country; opponents fear the move would lead to increasingly authoritarian rule. <br />The referendum could bring about the biggest change to the governing system since the modern republic was founded almost a century ago. <br />It also takes place under a state of emergency which was imposed following a failed coup last July. A government crackdown since then has seen tens of thousands of people arrested. <br />- BBC -