A number of major websites have gone down around the world, including the UK government web pages.
Those logging into to gov.uk have been faced with a message saying “503 Service Unavailable”.
Other sites affected include news outlets The Guardian, Financial Times, Independent, New York Times, Evening Standard, Bloomberg and Le Monde as well as Reddit, eBay and Twitch.
The Amazon retail website is also understood to be experiencing problems.
It is unclear what has triggered the widespread web outages, but service monitoring website Down Detector show a spike in reports of outages on Amazon Web Services.