Prices have been slashed by UK retailers to woo customers to shop on Boxing Day as extremely cold weather had affected pre-Christams shopping.
Many shops on high streets and malls across are offering heavy discounts and consumers are likely to be out in force to snap up bargains before the VAT jumps on January 4 to 20 percent from 17.5.
Large stores can only open for six hours because Boxing Day this year falls on a Sunday.
People coming into London are having to contend with a Tube strike which has left several lines suspended completely with others operating along only part of their route.
Businesses expect many people to shop online from the comfort of their own home to avoid the freezing conditions and travel problems.
Comparison website moneysupermarket.com predicted this year's aggregate Boxing Day sales could be the biggest ever, saying the UK is set to spend 323 million pounds online in a single day.
Selfridges expects 80,000 people to pass through the doors of its Oxford Street store, where it is offering discounts of up to 75 percent. More than an hour before the flagship shop opened, the queue of people waiting to get in stretched more than 100 metres.
A spokeswoman said: "Despite the fact we are opening at 11am due to Sunday trading, the first three shoppers started queuing at 11pm last night and by 4am there were 60 people waiting.
"We expect bags and shoes to sell really well, that's where shoppers will flock to first."