Two Russian nationals have been identified as suspects over the Salisbury nerve agent attack.
Police and prosecutors said there is sufficient evidence to charge Alexander Petrov and Ruslan Boshirov with conspiring to murder Sergei Skripal and attempting to murder the ex-Russian spy, his daughter Yulia and Wiltshire Police detective sergeant Nick Bailey.
Metropolitan Assistant Commissioner Neil Basu said the two suspects are aged around 40 and it is likely they were travelling under aliases and Petrov and Boshirov are not their real names.
Prosecutors will not be applying to Russia for the extradition of the two men, but a European Arrest Warrant has been obtained.
Mr Skripal and his daughter Yulia were poisoned in March by the nerve agent Novichok.
Sue Hemming, CPS director of legal services, said: "Prosecutors from CPS Counter Terrorism Division have considered the evidence and have concluded there is sufficient evidence to provide a realistic prospect of conviction and it is clearly in the public interest to charge Alexander Petrov and Ruslan Boshirov, who are Russian nationals."
Those offences include conspiracy to murder Sergei Skripal; the attempted murder of Sergei Skripal, Yulia Skripal and Nick Bailey; the use and possession of Novichok contrary to the Chemical Weapons Act; and causing grievous bodily harm with intent to Yulia Skripal and Nick Bailey.
"A realistic prospect of conviction means the CPS is satisfied on an objective assessment that the evidence can be used in court and that an objective, impartial and reasonable jury hearing the case, properly directed and acting in accordance with the law, is more likely than not to convict these two individuals of the charges," Ms Hemming said.
"It is of course for a jury to decide whether the evidence is enough for them to be sure of the suspects guilt.
"We will not be applying to Russia for the extradition of these men as the Russian constitution does not permit extradition of its own nationals.
"Russia has made this clear following requests for extradition in other cases. Should this position change then an extradition request would be made.
"We have, however, obtained a European Arrest Warrant which means that if either man travels to a country where an EAW is valid, they will be arrested and face extradition on these charges for which there is no statute of limitations."