'Mega Monday' turned out to be just that for online retailers as consumers flocked to buy their Christmas presents.

With sales volumes up 18% to £320m it was the biggest online shopping day of the year so far. But it was not the busiest, according to electronic retail industry body IMRG.

Research from IMRG member Hitwise showed traffic to retail sites amounted to 12.32% of all UK online visits. That made Monday December 8 the third busiest day in the sector, despite the high sales volumes.

Analysts say this suggests consumers have been busy at weekends researching gifts both in stores and online before purchasing the items on the internet the day after.

James Roper CEO of IMRG said: "Online sales are holding up well, considering the economic conditions, with both volumes and values significantly higher than last year.

"The ratio of researching to buying is also much greater, and researching started earlier this year, as Christmas shoppers work hard to track down the best deals."

But Jon Prideaux of payments service provider SecureTrading said it was a day of mixed fortunes for traders.

"The averages conceal that a significant number of retailers are facing a bleak Christmas with sales below last year - for others it's a bonanza with sales up very sharply.

"It is the first time that anyone can really say that about the e-commerce space where things generally just seem to get better and better for everyone. This Christmas is sorting out the wheat from the chaff."

'Mega Monday' followed the busiest weekend of the year on the high street with retailers offering huge discounts.

An estimated 1.5 million people flocked to London's Oxford Street and Regent Street on Saturday after the area was closed to traffic for the day.