Testing emergency alerts

The Energy and Environment Institute worked with the Environment Agency to test the public's response to cell broadcast emergency alert messages, as part of planning towards a national citizen emergency alert system.

Project summary

The Challenge

Cell broadcast warnings feature a unique and intrusive alert tone. How would the public respond to their mobile phones doing something new?

The Approach

We worked with the Environment Agency, Cabinet Office, Fujitsi and EE to field-test new cell broadcast mobile messaging technology on campus.

The Outcome

Results were presented to the Cabinet Office; the government chose cell broadcast as the preferred technology for the UK emergency alerting programme.

Lead academics

Project partners

The Cabinet Office


The Energy and Environment Institute

The Environment Agency

The Flood Innovation Centre


The Challenge

The Environment Agency has an existing the Flood Warning Service, an opt-in early alert service that sends text messages and automated voice calls to people who’ve elected to receive them.  Legislation was passed when the UK was in the EU mandating for all EU states to develop citizen emergency alerting for all emergencies.

Having tested both mobile messaging solutions (SMS text messaging and cell broadcast messaging) it was clear that cell broadcast was the most robust way of sending out emergency alerts.  However, there were technical challenges to doing this, and nobody knew how members of the public would react to this new type of message.  Cell broadcast messages are sent out directly from a mobile network tower to all phones within a specific area.  This makes cell broadcast robust and secure, but they also feature a unique and intrusive alert tone, and they override individual handset settings. How would the public respond to their mobile phones doing something new?

UK Emergency Alerts Cell Broadcast iPhone

The full research team

  • Dr Kate Smith Knowledge Exchange Fellow In Flood and Society

  • Dr Rob Thomas Senior Research Fellow in Geomorphology and Flood Risk

The Approach

Dr Rob Thomas and Dr Kate Smith of the Energy and Environment Institute worked with colleagues from the Environment Agency, the Cabinet Office, Fujitsu and EE to run a field-test of new mobile messaging technology, which uses cell broadcast to send emergency alerts to mobile handsets.

The University of Hull’s campus provided an excellent location to test the public’s response to cell broadcast messaging: with mobile phone masts on campus the technical team identified several locations where live test messages could be sent. Working closely with the team from the Environment Agency, we recruited volunteers from the University community to take part in the cell broadcast trial. In the end, technical challenges meant that we were unable to use the live network to send test messages to participants’ phones, so we used a range of different handsets provided by Fujitsu which displayed a realistic screen capture of a message being received.

We ran three workshops over the course of one day, facilitating focus group conversations and structured discussion with 90 participants in total. We asked participants what kind of emergencies they’d expect to receive a message for and what content they’d like to see in them. We ran the demonstration using the pre-recorded messages on Fujitsu’s handsets and asked participants to record their responses and reactions. Finally we carried out a hands-on activity to find out more about when participants would expect to receive a flood warning using cell broadcast.

Participants discuss their response to various emergency alerts during the on-campus testing

The Impact

The data shows that cell broadcast is an effective way of sending messages. People responded to the distinctive alert tone and unique message behaviour by saying that they would take action to protect themselves and their property. Many participants told us that as well as protecting themselves, an early response would be to reach out to vulnerable friends, family and neighbours to ensure that they could take action as well. Participants also emphasised the need for messaging technology to be fully accessible to users with different needs e.g. as well as an alert tone, messages could activate phone torch or flash.

Within weeks of completing the on-campus work, the initial results had been presented back to the Cabinet Office and resulted in the government deciding that cell broadcast would be the preferred technology for the UK’s emergency alerting programme. As the culmination of many years work by colleagues within the digital and flood warning services teams in the Environment Agency, this was a fantastic result and a worthy reward for everybody involved. Whilst the deployment of cell broadcast was impacted by the coronavirus pandemic and subsequent changes to government priorities, Government Digital Services have run several successful small-scale trials around the UK since June 2020. The first national trial will take place on 23 April 2023. Once up and running cell broadcast emergency messaging will make a real difference to public safety in the UK, saving lives and reducing losses from flood and other hazards.