The daughter of former Russian double agent Sergei Skripal may lead police to their would-be assassins after it was reported she had regained consciousness for the first time since being struck down in a nerve agent attack in the English city of Salisbury.
Yulia Skripal was "conscious and talking", according to reports yester, raising hopes that she may recover enough to be able to give the police information about the attack.
Such information could prove invaluable in the hunt for the suspected Russian hit-squad which targeted her and her father, who was convicted by the Russians for selling information to MI6 and went to Britain in 2010 following a spy swap.
Sergei Skripal, who collapsed with his daughter on a bench close to the River Avon in the city after leaving a restaurant, remains in a critical but stable condition.
It is understood doctors may have used a drug called pralidoxime, an antidote to organophosphate pesticides and chemicals, to treat her and her father. Salisbury District Hospital said her condition was "improving rapidly" and she was no longer in a critical condition.
Dr Christine Blanshard, medical director at the hospital, said: "I'm pleased to be able to report an improvement in the condition of Yulia Skripal. She has responded well to treatment but continues to receive expert clinical care 24 hours a day."
The Skripals' relatives in Russia had expressed fears that she was close to death and may even have already died.
Her improvement will be welcomed both by her family and detectives, who will hope that she recovers to the extent that she can respond in some way to questions about the hours leading up to the attack.
Yulia Skripal, 33, who lives in Moscow, was in Britain visiting her father and it may be that she can at some stage give an indication of whether they were followed or if she noticed any suspicious activity around her father's Salisbury house, where police say the largest concentration of traces of nerve agent was discovered.
David Videcette, a former counter-terrorism officer, said: "Officers will be hoping Yulia might be able to say something that indicates they were followed or that there was activity at the front of the house."
Detectives earlier said the pair were probably poisoned by a nerve agent being applied to Mr Skripal's front door at his home.
Britain has accused Russia of being behind the poisoning, something fiercely denied by the Kremlin. In turn, Russia has suggested that British intelligence officers may have been involved in the poisoning.