Today is expected to be the busiest online shopping day of the year, as retailers brace themselves for Cyber Monday.

Online sales are expected to hit between £450m to £605m today alone.

According to research from the Centre for Retail Research and, online sales will hit £605m today, an increase of 16% against last year, as six million shoppers take part in the spending spree.

Credit card firm Visa expects £450m to be spent today, also known as Mega Monday, with 7.7 million online transactions, up 16% year on year.

John Lewis is expecting to take 80,000 orders and Amazon predicts to generate more than 3.5 million.

It follows Black Friday, a US shopping day when retailers cut prices and offer promotions the day after Thanksgiving.

Visa and John Lewis said they expect the evening to be the busiest for online sales, peaking from 8pm to 9pm. Amazon expects sales to rise at 6pm.

Visa said data analysis shows that the busiest online shopping day historically falls on the Monday closest to the beginning of December.

During Monday, Visa expects £312,500 to be spent per minute, or £5,208 per second, on its cards online.

“UK consumers’ love affair with online shopping will reach its peak on Mega Monday,” said Jeremy Nicholds, director of commercial development at Visa Europe.

“Online shopping now accounts for more than 25% of spend with Visa in the UK, signifying the confidence that consumers have in the security of online payments and in the delivery of goods.”