British Prime Minister, Theresa May on Wednesday expelled 23 Russian diplomats.
She also suspended high-level contacts, including for the World Cup coming up in June.
The Prime Minister said her government has found Moscow “culpable” of a nerve agent attack on a former spy.
The British Prime Minister said she would be pushing for a “robust international response” when the UN Security Council meets later Wednesday in New York to discuss the attack on Sergei Skripal and his daughter on March 4.
Moscow has on several occasions denied any involvement and its London embassy warned that May’s response was “totally unacceptable and shortsighted.”
May told parliament that Russia had failed to respond to her demand for an explanation on how a Soviet-designed chemical, Novichok, was used in the English city of Salisbury.
She said, “There is no alternative conclusion other than that the Russian State was culpable for the attempted murder of Mr Skripal and his daughter.
“This represents an unlawful use of force by the Russian State against the United Kingdom.”
In measures drawn up at a meeting of her national security council earlier Wednesday, May announced that 23 Russian diplomats believed to be undeclared intelligence officers must leave Britain in a week.
She suspended all planned high-level contacts, which includes revoking an invitation for Foreign Minister Sergei Lavrov to visit but said she did not want to break off relations entirely.
May also confirmed that neither members of the royal family or ministers would attend the football World Cup in Russia later this year.
And she outlined fresh measures against people travelling to or living in Britain who were responsible for violations of human rights or planned “hostile activities.”