There was anger on Twitter after customers with a monthly "delivery saver" subscription were able to book prime slots for the days before December 25 a week in advance of other shoppers.
Shoppers said they stayed up until midnight on Monday and Tuesday to book Christmas delivery slots for December 23 and 24 respectively, which is when they became available to all customers for the first time.
But many complained that slots in their areas were already sold out as soon as they went live at one minute past midnight.
On Twitter, a Tesco spokesman explained that delivery saver customers were able to book slots for December 23 and Christmas Eve from November 26 and that the prime delivery spots were likely "booked up on that day".
When The Sun tried to book a one-hour delivery slot in a rural location today, the website stated that there are "no slots available" anytime between December 19 and 25.