Theresa May said the diplomats, who have a week to leave, were identified as “undeclared intelligence officers”.

The UK later told the UN Security Council that Russia had used “a weapon so horrific that it is banned in war” in a “peaceful” British city.

…Moscow refused to meet Mrs May’s midnight deadline to co-operate in the case, prompting Mrs May to announce a series of measures intended to send a “clear message” to Russia.

These include:

– Expelling 23 diplomats
– Increasing checks on private flights, customs and freight
– Freezing Russian state assets where there is evidence they may be used to threaten the life or property of UK nationals or residents
– Ministers and the Royal Family boycotting the Fifa World Cup in Russia later this year
– Suspending all planned high-level bilateral contacts between the UK and Russia
– Plans to consider new laws to increase defences against “hostile state activity”

Mrs May told MPs that Russia had provided “no explanation” as to how the nerve agent came to be used in the UK, describing Moscow’s response as one of “sarcasm, contempt and defiance.”

Russian spy: UK to expel 23 Russian diplomats – BBC News

hmmm