During the core holiday shopping period of November and December 2016, UK retail ecommerce sales will reach an estimated GBP16.90 billion ($28.83 billion) and 20.3% of all holiday season retail sales, up from GBP14.65 billion ($22.39 billion) and 17.8% last year. The increasing shift to smartphone buying in the UK will contribute to the ecommerce uptick during the Christmas period.