Rail travellers face paying up to twice as much for their Christmas getaway if they wait until December to book a ticket.
The cheapest fares for travel on Saturday, December 23, are expected to increase sharply over the next six weeks, figures published by ticket retailer Trainline show.
A forecast of price rises among the 10 most popular festive journeys in 2016 show Advance singles from Liverpool to London could rise from £17 now to £33 by the start of December.
The price will soar to £82.90 for those who wait to buy their ticket until they are about to board a train.
Other routes set to become more expensive over the next six weeks include Leeds to London (from £22 to £36), London to Edinburgh (from £68 to £81) and Peterborough to London (from £11 to £19).
Trainline said its customers saved a total of £24 million by booking tickets in advance for travel over the Christmas period last year.
A spokesman for the Rail Delivery Group, representing train operators, said: "Thanks to changes made by train companies, people can now buy cheaper Advance tickets as little as 10 minutes before travel on some routes and see when cheap deals are running out so they don't miss the best price.
"Where they can, we'd advise people who want the cheapest deals for travel over Christmas to book now."