Today millions of voters in Malaysia are heading to the polls in an election that the country's media has called the fiercest in history. The election has been described as a battle of old allies - Prime Minister Najib Razak is facing off against his 92-year-old former mentor Mahathir Mohamad. But the government is expected to clinch a narrow win. Our correspondent Rian Maelzer takes us to a polling station in Kuala Lumpur.