Britain's Prime Minister Theresa May, leaves 10 Downing Street in London, March 14, 2018. REUTERS/Toby Melville

LONDON (Reuters) - British Prime Minister Theresa May said on Wednesday she had come to the conclusion that Russia was culpable for the attempted murder of Sergei Skripal and his daughter.

Skripal, 66, and his daughter Yulia, 33, were found slumped unconscious on a bench outside a shopping center in the genteel southern English city of Salisbury on March 4. They have been in a critical condition in hospital ever since.

“There is no alternative conclusion, other than that the Russian state was culpable for the attempted murder of Mr Skripal and his daughter, and for threatening the lives of other British citizens in Salisbury,” May said.

“This represents an unlawful use of force by the Russian state against the United Kingdom,” she said.