Corbyn wants 'incontrovertible' proof before blaming Russia for Salisbury attack

Jeremy Corbyn has said he wants "incontrovertible proof" before blaming Russia for the Salisbury nerve agent attack.Inspectors from the Organisation for the Prohibition of Chemical Weapons earlier this week backed the Government's stance on the poisoning of former Russian spy Sergei Skripal and his daughter Yulia in the cathedral city last month.The OPCW confirmed the toxin used was novichok - a military grade nerve agent developed by Russia in the 1980s.