Visitors to the US and Canadian sites of online shopping company Amazon found the site offline for half an hour yesterday in the latest in a series of unexplained problems to hit high-profile websites.
The incident, which did not effect the UK site, came just days after Google was hit on Friday, including its Gmail, YouTube and Drive sites, as well a three-day long problem with Microsoft’s Outlook.com.

"It's very unusual to see such a number of high-profile websites all suffering peak-time outages within the course of a few days of each other," said Chris Green, principal technology analyst at the Davies Murphy Group consultancy.

"People are going to be very interested to know exactly what the reasons were for the incidents that are still unexplained because the implications are huge: we've seen everything from users being unable to see their email to visitors and third-party retailers who use Amazon's marketplace being unable to buy and sell goods - all happening seemingly with no warning."