An emergency alert system that highlights urgent tweets with potentially lifesaving text messages and pop-up notifications has been rolled out across Ireland and the UK.

57 new accounts have signed up for the programme, including the Garda Síochána, the 47 police forces in the UK, the London Fire Brigade and the UK Environment Agency.

From today, these organisations will now be able to highlight critical information to their Twitter followers by marking Tweets as alerts, which highlight a Tweet with an orange bell to make it more visible.

Twitter users who sign up for Twitter alerts from an account will receive notifications directly to their phone via text message. Twitter iPhone or Android users will also get a push notification direct to their mobile.

To subscribe to these notifications, Twitter users can go directly to an alert setup page for whatever account at twitter.com/[username]/alerts. See the Garda page at https://twitter.com/GardaTraffic/alerts for an example.

A similar system was launched in the U.S., Japan and Korea from September 2013. Since launching, the service has been used by international organisations to disseminate information during emergencies involving public safety, accessibility and bad weather.

All of the organisations participating in this new system already use Twitter as a tool to communicate important information to their followers.

Twitter says "The added functionality of Twitter Alerts will help them reach their followers with important and accurate information during emergencies, natural disasters or when other communications services aren't accessible".