Explainer: why UK terror threat has been raised to its highest level

Conditions that allow the activation of Operation Temperer, putting troops on the streets, are agreed at the highest level The international terrorism threat to the UK has been raised to critical, meaning an attack is expected imminently, in the wake of the Parsons Green bomb attack in London. It is the highest of the five levels used to describe the threat.Alongside the increased terror threat, phase one of Operation Temperer has been activated, meaning that up to 5,000 armed troops can be depl