Today is predicted to be one of the busiest internet shopping days according to retail experts as the Christmas shopping season begins in earnest.

Price comparison website Kelkoo in conjunction with the Centre for Retail Research predicted that consumers would spend £537m online today, a 29% increase on last year. Credit card company Visa said it was expecting to handle 3.8 million transactions throughout the day, nicknamed “Mega Monday” by some retailers.

Sales figures will be bolstered by Christmas sales and discount events launched for the day.

Some online giants believe however that next Monday, December 6, will be the biggest online day, rather than today. Amazon and Play.com predict they will see more sales on December 6 and have scheduled their Christmas deals then.

Online retailer body IMRG predicts that between midday and 1pm on December 6 will see the peak in internet shopping.

The biggest day on the high street is predicted to be Saturday December 18.