The UK is creating a new cyberforce unit which will have an offensive capability, the defence secretary has announced.
The new unit will also, if necessary, launch strikes in cyber space, Philip Hammond said.
The role of the unit is to protect computer networks and safeguard vital data.
Mr Hammond told the Conservative Party conference that “the threat is real. Last year, our cyber defences blocked around 400,000 advanced, malicious cyber threats to the government secure intranet alone,” he said.
In a statement, the Ministry of Defence (MoD) said the “creation of the “Joint Cyber Unit Reserve will allow it to draw on individuals’ talent, skills and expertise gained from their civilian experience to meet these threats”.
Mr Hammond told the Mail on Sunday clinical “cyber strikes” could disable enemy communications, nuclear and chemical weapons, planes, ships and other hardware.
He told the newspaper: “People think of military as land, sea and air. We long ago recognised a fourth domain – space. Now there’s a fifth – cyber. This is the new frontier of defence. For years, we have been building a defensive capability to protect ourselves against these cyber attacks. That is no longer enough.”
“You deter people by having an offensive capability. We will build in Britain a cyber strike capability so we can strike back in cyber space against enemies who attack us, putting cyber alongside land, sea, air and space as a mainstream military activity.
“Our commanders can use cyber weapons alongside conventional weapons in future conflicts.”
The MoD said the recruitment of reservists will target regular personnel leaving the armed forces, current and former reservists with the required skills and civilians with the appropriate technological skills and knowledge.
This announcement is highly significant as it is the first time that any government around the world has ever announced that it has an offensive cyber capability.