"A special flight will fly out tomorrow," the source said.
On March 14, UK Prime Minister Theresa May announced the largest expulsion of Russian diplomats from the UK since the Cold War, explaining the move by arguing that it was "highly likely" that Russia was responsible for the recent attack since the substance used to poison Skripal and his daughter Yulia was identified as a Novichok-class, military-grade nerve agent developed in Russia.
Skripal and his daughter Yulia were found unconscious earlier this month on a bench at a shopping center in Salisbury. Both of them remain in critical condition and are being treated for exposure to a chemical.
Previously, former Russian intelligence agent Skripal had been accused of espionage on behalf of London. He fled the country and was later granted asylum in the United Kingdom after a US-Russia spy exchange.