A British man poisoned with the Novichok nerve agent 10 days ago has regained consciousness and is now in a critical but stable condition.
Charlie Rowley, 45, was poisoned along with Dawn Sturgess, who died on Sunday, by the same nerve agent used in the attack on former Russian spy Sergei Skripal and his daughter in March.
"We have seen a small but significant improvement in the condition of Charlie Rowley," said Lorna Wilkinson, director of nursing at Salisbury District Hospital.
"He is in a critical but stable condition, and is now conscious."
Police have said Sturgess, who was Rowley's partner, handled an item contaminated by Novichok in southwest England, near Salisbury where Skripal and his daughter Yulia were struck down.
Novichok was developed by the Soviet military during the Cold War.
Britain and its allies blamed Russia for the attack on the Skripals, prompting a major Western expulsion of Russian diplomats. Moscow rejected the accusations and hit back by expelling Western diplomats.
The investigation became a murder hunt after the death of Sturgess, a 44-year-old mother of three, who lived in Amesbury, a town near Salisbury.
Her family paid tribute to her on Tuesday.
"Dawn will always be remembered by us as a gentle soul who was generous to a fault," they said in a statement released by London's Metropolitan Police.
"She had the biggest of hearts and she will be dreadfully missed by both her immediate and wider family."
Police are working to establish whether the Britons were exposed to the same poison used in the attack on the Skripals.
They said late on Monday they were transporting a vehicle from an address in Swindon, about 50km from Amesbury, in connection with the investigation.