London has the most expensive transport fares in the world, according to research carried out by the campaign team of Labour mayoral hopeful Dame Tessa Jowell.
Tube users pay more than double what the residents of any other major city in the world pays except Washington, according to the study.
According to the investigation a zone one to six fare costs more than three times the equivalent ticket in New York and four times more than Paris.
A study released earlier this week by transport information company Inrix showed that London's roads are the most congested of any city in Europe.
Ms Jowell, who has promised to freeze transport fares across the capital's transport network, said: "London is now the most congested city in Europe. That is bad for London's economy and bad for health.
"More affordable public transport is therefore important for many interconnected reasons. It's time Londoners are given a break from ever rising prices.
"If I become the next Mayor of London I will freeze fares as a first step and hope to go further. I'll introduce One Zone Weekends and one hour bus tickets to help Londoners get round our city."
The research compared fares in London with a list of the world's top 20 cities that have a metro system.
A peak time pay as you go single in London from zone one to six costs £5.10 and the daily price cap is £11.70. The study found that the next most expensive city is Washington DC where the highest fare would set you back £3.79 while a day ticket costs £9.32.