Salisbury attack: what has the UK said and what evidence does it have?

The revelation that scientists at the Defence Science and Technology Laboratory at Porton Down have not established that the nerve agent used to poison Sergei and Yulia Skripal was made in Russia has caused a storm.UK officials hurried to explain that the scientific findings were just one part of the intelligence jigsaw that pointed the finger for the Salisbury attack at Moscow.Unlike her foreign secretary, the prime minister was precise when she explained eight days after the attack why the gov