Amber Rudd: More than 250 counter-terrorism police investigating UK nerve agent attack

Investigators have been summoned for emergency talks on the crisis in Salisbury, where the fallout from a suspected nerve agent attack continues to widen.

5.17pm: Following a meeting of the British Government's Cobra committee, Home Secretary Amber Rudd said there were more than 250 counter-terrorism police involved in the investigation which was proceeding with "speed and professionalism".

Police investigating the Salisbury nerve agent attack have identified more than 200 witnesses and 240 pieces of evidence, Ms Rudd said.