Britons will receive a text message in the event of a nuclear attack.
A Cabinet Office spokesperson revealed that a scheme to text all mobile phones in the affected area was the most likely warning system.
The spokesperson said: "The UK has robust emergency management arrangements that are flexible, adaptable and applicable to a range of emergency scenarios.
"These include the capability to warn and inform the public through a range of channels including social and broadcast media platforms and direct alerts such as the flood warning system. We continue to keep these arrangements under review."
However, Anthony Glees, a security expert from the University of Buckingham, says the government shouldn't neglect television and radio broadcasts.
He said: "Text messages can only be a partial answer. New technology should underpin existing ones, such as radio and sirens, but must not and cannot replace them."