Russia responded in kind on Saturday, when the Russian Foreign Ministry summoned Laurie Bristow, the British ambassador to Russia, to tell him that 23 diplomats have one week to leave Russia "in response to the provocative actions of the British side and unsubstantiated accusations", according to a statement.
"We actually have evidence, which we've collected over the past 10 years, that Russian Federation not only worked on the development of nerve agents for the objective of committing murder but also created and stored [the substance] "Novichok", British Foreign Secretary Boris Johnson said to the BBC".
Mr Johnson claimed Putin's regime has spent a decade looking in to how to deploy deadly nerve agents across the world.
Writing in the Sun on Sunday two weeks after the March 4 incident which has left the Skripals in critical conditions, Mr Johnson said of Saturday's expulsions: "These futile measures will only punish ordinary Russians by depriving them of harmless opportunities to learn English and apply for United Kingdom visas".
Russians voted Sunday in an election set to hand President Vladimir Putin a fourth Kremlin term, as the country is embroiled in a crisis with Britain and its allies over a spy poisoning. Both are in hospital in critical condition.
UK Prime Minister Theresa May on March 14 accused Russian Federation of "an unlawful use of force" against her country.
"We will always do what is necessary to defend ourselves, our allies and our values against an attack of this sort, which is an attack not only on the United Kingdom, but upon the worldwide rules-based system on which all countries, including Russian Federation, depend for their safety and security", Bristow told reporters after being informed of the expulsions.
He branded the British investigation "untransparent and secret", adding that there was "no proof" that Skripal was gravely ill.
Meanwhile, counter-terrorism police renewed their appeal for sightings of Mr Skripal's burgundy BMW 320D saloon vehicle, registration HD09 WAO, in Salisbury on the morning of Sunday, March 4.
Alexei Navalny claimed last night that kicking Kremlin spies out of London would only help the Russian president.
On Friday, Russia said it could hit back at Britain at "any minute" with its own raft of punitive measures. Moscow took retaliatory measures, giving British ambassadors a week to pack.
"All the steps will be well thought out", Peskov said.
A day of voting across Russia's 11 time zones began at 2000 GMT on Saturday on Russia's eastern edge, in the Pacific coast city of Petropavlovsk-Kamchatsky.
Pre-election polls have placed Putin, the country's longest-serving leader since Soviet dictator Joseph Stalin, as a clear front-runner, reports CNN.
Speaking on the Marr Show, Putin's European Union ambassador Vladimir Chizhov suggested Britain or America might be behind the novichok used to poison Mr Skripal and his daughter Yulia.
Many Russians remain sceptical that the state was responsible and some analysts have not ruled out the involvement of ordinary criminals or rogue agents.
Vladimir Chizhov said the military-grade Novichok poison might have originated at Porton Down as it was only eight miles from the scene in Salisbury.