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Media captionThe latest on the clean-up and the investigation in Salisbury
Traces of the nerve agent employed against former Russian snoop Sergei Skripal and his daughter, Yulia, have been found at the restaurant where they feed on Sunday afternoon, the BBC understands.
The substance was found in one part of Zizzi in Salisbury during a continuing forensic examination.
The pair were found two hours after finishing their meal collapsed on a park bench. Both are critically ill.
No-one who was in the restaurant at the same day is thought to be in danger.
There is also no suggestion that anyone dining at the time had anything to do with the nerve agent.