The health of former Russian spy Sergei Skripal's daughter Yulia is "improving rapidly", the hospital that has been treating them since they were found unconscious following a nerve agent attack said Thursday.

File photo: Sergei Skripal (R) and Yulia Skripal(L)

Yulia Skripal is "improving rapidly and is no longer in a critical condition," Salisbury NHS Trust said in a statement, adding that her father remains in a critical but stable condition.