Two Russian nationals have been named as suspects in the attempted murder of former Russian spy Sergei Skripal and his daughter Yulia.
There is “sufficient evidence” to charge Alexander Petrov and Ruslan Boshirov over the attack in Salisbury, Scotland Yard and the CPS say.
They are thought to have been using the names as aliases and are about 40.
Mr Skripal, 66, and his daughter Yulia, 33, were poisoned with nerve agent Novichok in March.
The CPS is not applying to Russia for the extradition of the two men, as Russia does not have extradition agreements with the UK. A European Arrest Warrant has been obtained in case they travel to the EU, however.
In response, the Russian foreign ministry has said the names and photographs of the men “do not mean anything to Moscow”.
Police are now linking the poisoning to an attack on 30 June, when Dawn Sturgess and Charlie Rowley fell ill at a house in Amesbury, about eight miles from Salisbury.
Ms Sturgess died in hospital on 9 July. Mr Rowley was discharged from hospital on 20 July.
Sue Hemming, CPS director of legal services, said there was enough evidence “to provide a realistic prospect of conviction” and that it was “clearly in the public interest to charge Alexander Petrov and Ruslan Boshirov”.
The 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.
Det Sgt Nick Bailey also fell ill after responding to the incident in Salisbury.
Scotland Yard’s Assistant Commissioner Neil Basu, the head of UK counter-terrorism policing, said on Wednesday he “continues to make good progress but remains off work”.
The Metropolitan Police said the two men had arrived at Gatwick Airport from Moscow on 2 March and stayed at the City Stay Hotel in Bow Road, east London.
From there, they travelled to Salisbury on 4 March where Mr Skripal’s front door was contaminated with Novichok.
Officers believe a perfume bottle was used to spray the door.
There is no risk to other guests staying at the hotel at the time, police said.
Police said Ms Sturgess and Mr Rowley were later exposed to Novichok after handling a contaminated container, labelled as Nina Ricci Premier Jour perfume.
Mr Rowley has told police he found the box containing the small bottle and an applicator in a charity bin.
He tried to put the two parts together and got some of the contents on himself. His partner Ms Sturgess applied some of the contents to her wrists and became unwell.
Mr Basu said: “We don’t yet know where the suspects disposed of the Novichok they used to attack the door, where Dawn and Charlie got the bottle that poisoned them, or if it is the same bottle used in both poisonings.”
But he added that “the manner in which the bottle and packaging has been adapted makes it a perfect cover for smuggling the weapon into the country, and a perfect delivery method for the attack against the Skripal’s front door”.
But Mr Basu confirmed that the two cases were related, saying: “We have now linked the attack on the Skripals and the events in Amesbury which affected Dawn Sturgess and Charlie Rowley.
“It now forms one investigation. We do not believe Dawn and Charlie were deliberately targeted, but became victims as a result of the recklessness in which such a toxic nerve agent was disposed of.”
Prime Minister Theresa May is due to make a statement in the House of Commons shortly, to update MPs on the Salisbury investigation.