Click For Photo: https://ichef.bbci.co.uk/images/ic/1024x576/p060xmb5.jpg
Media captionTheresa May: Spy poisoned by "military-grade nerve agent"
Former spy Sergei Skripal and his daughter were poisoned by a military-grade nerve agent of a type developed by Russia, Theresa May has told MPs.
PM - Russia - Salisbury - Attack
The PM said it was "highly likely" Russia was responsible for the Salisbury attack.
The Foreign Office summoned Russia's ambassador to provide an explanation.
Mrs - May - Response - End - Tuesday
Mrs May said if there is no "credible response" by the end of Tuesday, the UK would conclude there has been an "unlawful use of force" by Moscow.
The chemical used in the attack, the PM said, has been identified as one of a group of nerve agents known as Novichok.
Mrs - May - Action - State - Country
Mrs May said: "Either this was a direct action by the Russian state against our country, or the Russian government lost control of its potentially catastrophically damaging nerve agent and allowed it to get into the hands of others."
She said Foreign Secretary Boris Johnson had told the ambassador Moscow must provide "full and complete disclosure" of the Novichok programme to international body the Organisation for the Prohibition of Chemical Weapons.
Mrs - May - UK - Measures - Commons
Mrs May said the UK must stand ready to take much more extensive measures, and these would be set out in the Commons on Wednesday should there be no adequate explanation from Russia.
What are Novichok nerve agents?
UK - Retaliate
How could the UK retaliate?
Retired military intelligence officer Mr Skripal, 66, and his daughter, Yulia, 33, were found slumped on a bench in Salisbury city centre on Sunday 4 March. They remain in a critical but stable condition in hospital.
Det - Sgt - Nick - Bailey - Pair
Det Sgt Nick Bailey, who fell ill attending the pair, remains seriously ill, but has been talking to his family.
Mr Skripal was convicted by the Russian government of passing secrets to MI6 in 2004, but given refuge in the UK in 2010 as part of a "spy swap".
Home - Secretary - Amber - Rudd
Home Secretary Amber Rudd will chair...
Wake Up To Breaking News!