It is a controversial deal with a controversial leader. But Ken Livingstone defended his agreement to bring cheap oil to the capital from Hugo Chavez's Venezuela as he announced how it will benefit Londoners. The Mayor says a quarter of a million people will qualify for discounted bus and tram travel. Anyone on Income Support can apply for a special Oyster card which will see them paying fifty pence for a single bus fare. That's half the current cost of the same journey on a normal Oyster card - and a quarter of the current cash fare.