A system of mobile phone alerts informing residents about major emergencies will be tested on more than 50,000 people.
Messaging that would allow the public to be updated on natural disasters, terror attacks or large-scale accidents will be piloted in Yorkshire, Suffolk and Glasgow over the next few months.
Cell broadcasting, which allows messages to be sent out to every active handset near a chosen mobile mast without the need for individual telephone numbers, will be tested along with text messages sent out using the locations of phones tracked by mobile network operators.
The pilots, in Easingwold in North Yorkshire, Glasgow city centre, and Leiston in Suffolk, will assess how well the technology works and how the public reacts to it.
Cabinet Office minister Francis Maude said: "The Government and three mobile phone companies, O2, Vodafone and EE, will conduct separate tests later this year to look at a how different technologies work and how the public react when they receive an emergency alert to their phone.
"I want to reassure the public that these tests are not linked to any threat or specific hazard in their area. We have included diverse areas - both rural and urban - as part of our tests, as we want to look at how effective the different systems are in different areas in using mobile phones to deliver mass messaging.
"Messages will be sent to mobile phones in the test areas by SMS in parts of Suffolk and Glasgow, and by SMS and cell broadcasting in parts of Yorkshire. In total, approximately 50,000 people across the three areas may receive the messages.
"The message itself will make clear that it is only a test and I do not want the public to be alarmed in any way.
"We are also looking for help from the public in evaluating how well the tests worked and how they felt about receiving messages in this way and we would welcome the public's views which they can provide via an online survey or a series of focus groups."