Decision to raise terror level to critical will see 5,000 troops on streets

Move following Manchester bombing will be third time UK has been at highest level since inception, with soldiers to be deployed under Operation TempererThe decision to raise the official threat level to critical and to deploy troops under Operation Temperer, meaning that an attack is expected imminently, is the first time for a decade that it has been set at its highest level.The last time troops under Operation Temperer were deployed was immediately after the terrorist attacks in Brussels last