Ken Livingstone revealed his first manifesto pledge of the mayoral race by announcing plans to make travel for the over-60s easier if re-elected.
Extending the hours of the Freedom Pass will cost £20m
Mr Livingstone said he would extend the Freedom Pass to operate 24 hours a day across London's bus, Tube, rail and tram network.
Currently the Freedom Pass starts on most public transport at 0900.
If re-elected Mr Livingstone has said the change would be implemented within the first 12 months of his next term.
"Four out of five Londoners over the age of 60 are retired but they regularly tell me that because of appointments, trips and other issues they need to travel before 9am.
"Extending the operating hours of the Freedom Pass will give these Londoners 24-hour flexibility to travel free."
The cost of extending the Freedom Pass to 24 hours a day will be £20m.
But Mr Livingstone said on the basis of current strong Transport for London revenues, there would be no increase in fares to fund the pledge.
He added: "This policy is part of my central goal of ensuring that London's public transport system is reliable and open to every Londoner."
No fare decreases
Later, he told BBC London: "I think fares in this city are about 30 or 40% higher than they should be."
But he added that fares could not be brought down unless train companies agreed, "and that's their profits, they're not going to do that".
He said that fares could not be reduced unless the governemnt was prepared to subsidise London's transport by another £1 bn.
He also said the money raised so far by fare rises - including the 60% increase in the congestion charge from £5 to £8 - had helped improves London's transport system and that it only needed "finessing".