Thousands of people have been left stuck in online queues to book a Tesco Christmas delivery slot.
Some complained they were "kicked out" of the Tesco app and the site crashed as queues of more than 275,000 were reported on Tuesday, with one Twitter user calling it "shambolic".
Delivery Saver customers were told they could book a slot from 6am on 15 November, but some complained that the queue was opened before the advertised time.
Posting on Twitter, one customer said: “I logged on at 5.59 (am) to get ready only to find over 135,000 in the queue already.”
By 6.13am, users were posting screenshots that showed the queue was up to 180,000 people.
Others complained they spent time waiting in the queue only to be kicked out: “Hey @Tesco just sat for half an hour in your xmas queue and as soon as I reached the front of the queue I got kicked out and now the wait is an hour.”
Another said: “I was 38,000 in the queue and the app ‘refreshed’ itself and now I’m number 178,000. You’re having a laugh.”
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One wrote: "Seriously @Tesco this is twice I’ve now been kicked out of the app and put to back of the queue. What exactly am I paying for with the delivery saver".
One user reported being at the back of a queue of 275,000, and posted: "Useless Christmas booking queue. Was down to less than 5,000 ahead and then your app started repeatedly self updating."
Another tweeted: "Tesco Christmas queue system broken again! Started 63,489 in the queue at 5:50am. Have since been bumped down to 175,563 despite not leaving the app, not refreshing etc. Tesco sort it out! Not good enough!"
Tesco apologised to its customers.
A spokesperson for the supermarket told Yahoo News UK: “We’re currently seeing a high number of visits to our website and Groceries app and some customers are temporarily having difficulty logging on or placing orders.
"We're really sorry about this. There are still slots available for both home delivery and click & collect over the Christmas period and we’re working to get things back up and running as quickly as we can.
"In the meantime, we recommend that customers use our website to place their order.”