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.