Mobile traffic has been growing at a reliably fast pace for the past few years, but during Christmas it rocketed.

The headline figures came from John Lewis and Amazon. At John Lewis, mobile accounted for 75% of traffic on Christmas Day, and managing director Andy Street predicted total online sales will account for half of all John Lewis sales in the next five to 10 years.

At Amazon, meanwhile, “around half” of Christmas shoppers used mobile devices to buy, it said, and five toys were purchased every second on mobile between Thanksgiving on November 28 and Cyber Monday on December 2.

An IBM report suggested mobile accounted for 48% of all online traffic on Christmas Day.

The figures show how quickly having a strong mobile offer has become non-negotiable. Christmas Day is unusual, because more people sit inside than normal, but the sector would be wise to take note of the trends of retail’s busiest trading period.