Britain said on Thursday that Russian President Vladimir Putin had "ultimate" responsibility for a nerve agent attack on a former Russian double agent in England, as it prepared to brief the UN Security Council.

London has accused two members of Russian military intelligence of using Novichok to try to kill former Russian spy Sergei Skripal and his daughter Yulia in Salisbury. Security Minister Ben Wallace said Putin bore ultimate responsibility for the poisoning. "Ultimately he does in so far as he is the president of the Russian Federation and it is his government that controls, funds and directs the military intelligence, the GRU, via his ministry of defence."