According to Tube upgrade contractor Tube Lines, the first Friday in December is the day more people choose to take off, and spend their November pay packet on Christmas shopping. Or themselves.
Last year on the same day - Friday 7 December 2007 - 4.17M passengers used the transport network to shop.
This year extensive sales are predicted to draw people to the shops.
Tube Lines' director of operations Lee Jones said: "Based on last year's passenger numbers we are expecting an extra 80,000 people to travel on our three lines on 5 December to do their Christmas shopping.
"This is on top of the 2M people who use our lines daily. That is a lot of passengers to move around the capital and the challenge is on us to keep trains and stations clean and services running reliably.
"If we go by last year’s figures we expect the number of cleaning and litter faults to rocket so my teams will be on the ready to ensure trains and stations remain litter free and spillages are mopped up as they turn around at stations at the end of each line."