Sadiq Khan today defended a controversial perk for thousands of Londoners who live with transport workers.
The mayor's Tory rival in May's election claimed scrapping the free pass would release £44m to spend on tackling knife crime.
But Mr Khan said there was no cost to the 'nominee pass' scheme and Transport for London workers would expect higher salaries if it was abolished.
TfL employees are entitled to two complimentary travel cards - one for themselves and one for a friend, partner or relative living at the same address.
Bus workers and some TfL pensioners can also claim free travel. A total of 52,000 nominee passes are currently in use.
Conservative mayoral candidate Shaun Bailey accused Mr Khan of failing to divert 'every penny you have' to fighting crime.
Mr mayor, your budget has provision to pay for TfL nominee passes. We calclulate at least £44m. Why was this money not directed to crime reduction? The point is, a loss in revunue, isn't it? Monies that would be coming to the GLA, to TfL. This is just another example of you not using every power you have, every penny you have to address crime in London.
There is no cost to TfL because the number of journeys is a tiny proportion of the 11m tube and bus journeys made per day, meaning no additional services need to be operated. The nominee pass is offered to TfL employees as part of an overall package. We the nominee pass removed from this package, other parts of the package including pay would need to be enhanced.