Passengers have overpaid by nearly £200 million to travel on London's public transport since 2015 because they bought paper tickets, according to new research.
Transport for London (TfL) figures show 37 million peak daily travelcards were purchased in the four-and-a-half years to July despite them being more expensive than using an Oyster card or contactless payment card.
Consumer website MoneySavingExpert.com - which obtained the data through a Freedom of Information request - calculated that passengers who bought the paper travelcards spent at least £184 million more than if they had used other payment methods.
It described paying for public transport in London as "daunting" and warned that first time visitors are particularly at risk of overpaying.
Travelcards entitle passengers to unlimited travel by London Underground, bus, tram or train within certain fare zones in the capital.
But the same journeys can also be paid for by Oyster or contactless cards, which have lower daily price caps for multiple trips.
Under current rates, passengers buying a peak daily travelcard pay £3 more for zones 1-4 and £5.80 more for zones 1-6.
Paper ticket holders overpay by an even greater amount when they do not travel in all the zones paid for or make enough journeys to reach the equivalent Oyster or contactless daily cap.
MoneySavingExpert.com consumer expert Johanna Noble said: "With so many peak daily travelcards still being sold, it's clear that many London travellers still aren't aware that there are cheaper options available.
"It's a travesty that passengers - many of whom are likely just to be visiting the capital rather than commuting in - have been overpaying to the tune of 184 million since 2015, with transport in London already so expensive. "It begs the question why these peak daily travelcards are still being sold at such an inflated price."
TfL chief technology officer Shashi Verma said: "Using Oyster or contactless to pay as you go is now the most popular way to travel by public transport in London, with around 63% of all Tube journeys now made this way. "These methods of payments are quick, easy and secure, and are better value than buying a one day paper travelcard.
"We run a promotional campaign, which includes station posters and announcements and information on our website, to encourage customers to use these methods.
"Over the last five years the number of people buying paper tickets has reduced by two-thirds, however some customers still prefer purchasing paper tickets and this is often out of habit."