Former Russian spy critically ill in Britain after exposure to unidentified substance

A former  Russian spy is in critical condition.   He was taken to intensive care  in the UK on March 4 after being exposed to an unknown substance.   The man is 66-year-old Sergei Skripal, according to a source close to the investigation.   He is a former spy who was convicted in Russia in 2006 of spying for Britain.    He was granted refuge in the UK after a spy swap between the U.S. and Russia in 2010.   Without providing any names, police said a 66-year-old man and a 33-year-old woman were found unconscious on a bench in Salisbury on Sunday.    (SOUNDBITE) (English) WILTSHIRE POLICE'S TEMPORARY ASSISTANT CHIEF CONSTABLE, CRAIG HOLDEN, SAYING: "They are currently being treated for suspected exposure to an unknown substance. Both are currently in a critical condition in intensive care."   Relations between the UK and Russia have been strained since 2006.    That year, former KGB agent Alexander Litvinenko was poisoned in London.   A British inquiry said his death was probably approved by Russian President Vladimir Putin. Credit: Reuters