Fraudsters will launch nearly one million cyber attacks a day on UK online retailers during a key shopping week in the run-up to Christmas.
Analysts believe criminals will focus on buying consumer electronics including games consoles and mobile technology as the number of internet shoppers surges over so-called Black Friday and Cyber Monday.
The consumer bonanza is an American trend that has spread to the UK, with Black Friday, now Britain's biggest shopping day, falling the day after Thanksgiving.
The following Monday has been branded Cyber Monday, when online deals take centre stage. Black Friday is on November 25 this year, while Cyber Monday is on November 28.
Cybercrime prevention company ThreatMetrix is predicting 6.5 million cyber attacks on UK retailers during that week.
Britain broadly experiences around 13% of global attacks on online retailers, and there are predicted to be around 50 million worldwide that week.
In the same period in 2014 globally there were 11.4 million attacks, and in that week in 2015 there were 30 million, and experts believe they will see a rise to 50 million this year.
During the final three months of 2016 there are expected to be around 20 million attacks on UK shopping websites, up from 16.5 million between July and September.
Worldwide, there were 76 million blocked online transactions in those three months, a 60% rise on the same period in 2015.