Update: Elon Musk makes a bid to buy Twitter

Tesla boss Elon Musk has offered to buy Twitter, saying he is the right person to "unlock" the social media platform's "extraordinary potential". In a surprise announcement, Mr Musk said he would pay $54.20 a share for Twitter, valuing it at about $40bn. We get the details from the BBC's Michelle Fleury in New York, and further analysis from tech journalist Chris Stokel-Walker. And Chris Low explains how Twitter's share price moved today in reaction to the news.