British scientists have developed a computer program they say can map the mood of the nation using Twitter.
Named Emotive, it works by accessing the emotional content of postings on the social networking site.
The team, from Loughborough University, say it can scan up to 2,000 tweets a second and rate them for expressions of one of eight human emotions.
They claim Emotive could help calm civil unrest and identify early threats to public safety.
More than 500 million people across the world use Twitter, and more than 340 million tweets are posted daily.