The UK intends to submit a request to Moscow to extradite two Russians suspected in the attack scout Sergei Skripal and his daughter with the help of a "Beginner", according to the Chronicle.info with reference to the channel 112.
The Guardian report that hundreds of officers from the police and intelligence agencies have spent months investigating, and have pieced together the movements of two Russians who came into the United Kingdom and left.
But the extradition request is expected to be rejected by Russian Federation, the paper added.
A CPS spokeswoman told Metro it was aware of the Guardian's report but had no comment to make.
Both are suspected of poisoning Sergei Skripal, a former double agent, and his daughter, Yulia, on March 4 with Novichok, a military-grade nerve agent developed by the Soviet Union during the Cold War.
The move was reciprocated by Moscow. Russian Federation denies any involvement in the attack.
Any extradition request put to Russian Federation is likely to be rebuffed, and The Guardian said there had been intense debate within the British government about whether to bother trying.
They say the Crown Prosecution has prepared an extradition request and it is ready to file, according to sources from Whitehall.
"This is Litvinenko all over again".
Russian officials refused to hand over the men wanted for the murder of Alexander Litvinenko with a rare radioactive isotope in 2006. "The police have managed to identify the people coming over and going back again", a Whitehall source said.
The Russian constitution forbids the extradition of Russian citizens to another state.
Her partner, Charlie Rowley, was also sickened by the poison in the bottle, but later recovered.
Rowley said he had found a perfume bottle which he gave to Sturgess, which she sprayed on her wrists. And the query would worsen the diplomatic row between Britain and Russian Federation. One died days afterwards.