Italian Prime Minister Enrico Letta announced his resignation Thursday, clearing the way for Matteo Renzi – the upstart leader of his centre-left Democratic Party (PD) – to take over his job.The 39-year-old Renzi was elected PD leader in December. Since then, he accused the government of failing to implement promised reforms and boost the economy, though he insisted until last week that he was not working to unseat Letta.President Giorgio Napolitano was due to receive Letta’s resignation on Friday. He was then expected to launch consultations with political leaders, before reaching the foregone conclusion that the premiership should pass on to Renzi.