Voting began Sunday morning in a presidential runoff election in Colombia widely expected to be won by conservative candidate Juan Manuel Santos. Opinion polls give the former defence minister up to 65 per cent of the vote. His opponent, former Bogota mayor Antanas Mockus, was at 28 per cent for the second-round election, dpa reported. The runoff is necessary because Santos only won 46.6 per cent of the vote in the May 30 first round, short of the required 50 per cent. -- SPA