Flash-sale days, such as Black Friday and Cyber Monday, led to 37 million shoppers being attacked by cyber criminals.

According to to data by web security company Blue Coat the sea change in shoppers using computers, smartphones, and tablets to make their festive purchases has led to an increase in cyber crime activity.

The research revealed that phishing attacks have increased two-fold over the last two years, with each successful attack costing an individual $886 (£539, €645) on average.

(Infographic: Blue Coat)
(Infographic: Blue Coat)