A 38% reduction in traffic has caused the shortfall in the authority's books. The new Oyster cards will clamp down on fare evasion, which TfL estimates costs some 3-4% of its £1.9bn revenue in tube and bus collections, amounting to £76m.

Jay Walder, managing director of finance and planning at TfL, told Accountancy Age that new electronic tickets, Oyster cards, launched last month would 'help' to reduce the loss on 'all' types of fare evasion.

Among the most common forms of fare evasion is the re-use of lost or stolen tickets. The new electronic Oyster card system enables TfL to 'switch off' stolen cards so they can no longer open barriers.

Another example of fare evasion is the black market selling of abandoned day tickets. In the new system, travellers keep their Oyster card even when the electronic ticket on it has expired.

The first cards were released to travellers who bought season tickets online. In the autumn, the cards will be available at station ticket offices and to travellers buying non-seasonal tickets. The cards will also allow TfL to introduce off-peak pricing for the Underground.

The Jay Walder profile contains more information about the introduction of the cards and attempts to bring the transport system of London back up to scratch.