The problems first seemed to start just before 9am GMT, and seem to largely be focused on Europe, although a heatmap of issues on DownDetector.co.uk shows the problem beginning to show up to a lesser extent in other countries.
Twitter’s API status checker is also reporting problems for several services.
For some people, tools like TweetDeck will load, but not show the most recent tweets, while for others there’s no joy at all.
We’ll update this story when the service recovers.
Update: Twitter Support tweeted that the company is trying to fix the issue.
Some users are currently experiencing problems accessing Twitter. We are aware of the issue and are working towards a resolution.
— Twitter Support (@Support) January 19, 2016
Update 2, 10:50GMT: Twitter appears to largely be returning to normal service for many people, although there are still a few reports of issues.
Update 3, 12.20GMT: The service still appears to be struggling, with some users finding they can intermittently access the service and problems persisting for others.
Update 4, 15:30GMT: Twitter now appears to be back to normal for most people. Phew.
Update 5, 18:00GMT: The problem is now fixed, and was caused by a code change, according to a spokesperson:
“The intermittent issue affecting some users between 00:40 to 06:50 PST has now been resolved. The issue was related to an internal code change. We reverted the change, which fixed the issue. Thank you for your patience.”