Amazon claims 2015 Black Friday was its biggest sales day in the UK ever, with more than six million items being ordered. This beats the record of 2014 when the company sold more than 5.5 million products at a rate of 64 items per second.

"For the second year straight, customers in the UK have blown us away with their response to the many great deals on great products that we've made available for Black Friday. On behalf of all of us at Amazon and our many hundreds of sellers who are also offering great deals, we would like to thank our customers for choosing to shop with us and for making it a day for the record books," Christopher North, managing director of Amazon UK, told the Press Association.

Black Friday online shopping

The majority of consumers opted for online, rather than physical store purchase, causing the websites of the country's well-known retailers' to go down due to the volume of incoming traffic. This was in line with what Experian-IMRG predicted ahead of Black Friday sales. According to new estimates by Experian, in conjunction with IMRG, the UK online retail sales are expected to hit £1.07bn on Black Friday, a 32% increase over £810m in 2014.

Justin Opie, managing director at IMRG, said: "The size and scale of Black Friday 2014 took everyone by surprise, overwhelming some carrier and retailer operations, as order volumes came in at a full 30% higher than expectation. All the indicators point to a much larger Black Friday this year – both in terms of greater numbers of retailers taking part and growing shopper interest – so the opportunity is vast, but there are many things to consider if it is to be managed efficiently and effectively."

Online chaos

With the heavy traffic, John Lewis's site went down around 3.20pm on 27 November, and according to one estimate, the company might have lost some £2.8m due to this. "This down time is undoubtedly expensive for John Lewis. They report annual online revenues of £1.4 billion and here at Capacitas we typically see 2% of demand taking place on Black Friday. In addition 10% of the Black Friday day's sales take place in the peak hour. This means an hour of downtime on the John Lewis website could amount to £2.8m in lost revenue," said Danny Quilton, chief technology officer at Capacitas.

Meanwhile, the Argos site slowed down and its page load time exceeded 10 seconds, when compared to 0.5 seconds page load time for Amazon. Argos, however, responded to customers' concern saying: "Order confirmations are taking longer than normal. Please sit tight, confirmation will be with you shortly."

The Tesco website was even reported to have been throwing up errors, with 8.4 seconds of page load time. But the retailer denied any issues on Twitter saying: "Our website is fully operational. We're very happy with our site speed. Feedback from customers today has been very positive #justsaying."

PC World claimed its biggest-ever start with eight sales per second and 100 large screen TVs selling in per minutes online. It claimed to have 400,000 visitors per hour to its site, an increase of up to 70% over 2014.