Yulia was discharged from the hospital earlier this week and is being kept in an unknown location. The central element of Britain's case against Russian Federation is the unusual nerve agent used in the attack, which was developed in Soviet laboratories during the last years of the Soviet Union.
Sir Mark said: "There is no plausible alternative explanation", adding that Russian Federation had continued to produce and stockpile small quantities of Novichok within the last decade.
The Skripals have been in Russia's sights for some time, or so alleged the United Kingdom on Friday.
Mr Sedwill added Moscow had a proven record of state-sponsored assassinations and had tested ways of delivering chemical weapons, including the use of door handles to spread nerve agents, as Britain believes was done in the Skripal case.
The claims come after the global Organisation for the Prohibition of Chemical Weapons backed Britain's assertion the Skripals were poisoned by Novichok - a military grade nerve agent developed by the Russians in the 1980s.
He pointed to the Owen Report from the UK's public inquiry into the death of Aleksandr Litvinenko which concluded in 2016 that he was "deliberately poisoned with Polonium 210, that there was a "strong probability" that the FSB (Russia's security agency) directed the operation, and that President Putin "probably approved it".
National Security Adviser Mark Sedwill accused the country of spying on Sergei Skripal and daughter Yulia for a minimum of five years, and offered some specifics in a letter sent to NATO Secretary-General Jens Stoltenberg on Friday, reports Reuters.
In an analysis of samples taken from the home of the Skripals, the highest concentrations of toxic chemical novichok, thought to be responsible for their poisoning, was found on door handles. It says that Russian Federation continued to produce the agents after the breakup of the Soviet Union, but did not declare the work to the Organization for the Prohibition of Chemical Weapons.
"We have zero information from officials in London about what is going on with her".
The Organisation for the Prohibition of Chemical Weapons (OPCW) - the worldwide chemical watchdog - confirmed on Thursday that the Skripals were poisoned with a toxic chemical of "high purity".
Moscow has hit back by expelling Western diplomats, questioning how Britain knows that Russian Federation was responsible and suggesting it stemmed from a plot by British secret services. She said Moscow will continue to press Britain to share evidence in the case.
He also questioned the authenticity of a statement issued by Ms Skripal through the Metropolitan Police saying she did not want to meet Russian officials.
"In the interest of transparency, and because unlike the Russians we have nothing to hide, we have asked the OPCW to publish the executive summary for all to see", Mr Johnson said in a statement.
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