Twitter is back up and running after major problems hit the social media website on Thursday afternoon.
Users from around the world reported difficulties logging onto the site after problems started at about 17:00 BST.
A statement posted on the site earlier said engineers were working to resolve the issue.
The last major outage in the UK was on New Year's Day when the site crashed after becoming overloaded.
Twitter communications said in a tweet: "Today's outage is due to a cascaded bug in one of our infrastructure components. We'll provide updated information soon."
There continued to be intermittent problems with the site on Thursday evening.