The daughter of former Russian spy Sergei Skripal may lead police to her would-be assassins after it was reported she had regained consciousness for the first time since she was struck down in a suspected nerve agent attack in Salisbury.

The BBC reported Yulia Skripal was "conscious and talking". It was claimed she had nerve agent on her left hand, and her father had it on his right hand.

Salisbury Hospital said her condition is “improving rapidly” and she is now no longer critical, raising hopes that she may recover enough to be able to give the police valuable information about the attack.

Such information could prove invaluable in the hunt for the suspected Kremlin hit-squad which targeted Col Skripal, who was convicted by the Russians for selling information to MI6 and came to Britain in 2010 following a spy swap.

Russia has denied it was behind the attempted murders. On Thursday, it announced the expulsion of more than 150 diplomats, including 60 Americans, in retaliation for the wave of Western expulsions of Russian diplomats over the poisoning.