The British government is considering allowing Russian officials to visit Yulia Skripal, who is recovering from a nervous attack with her father, Sergei, at the hospital.
Mrs. Skripal is aware and talks after she was poisoned with Novitschok while visiting her father in Salisbury
The police treated the poisoning as an attempted murder. The attack has led to global diplomatic plunder as Western nations joined the UK in expelling Russian officials.
The former Russian spy, Mr. Skripal, has been in critical condition since 4 March.
The Russian Embassy in London said in a tweet on Friday that it "insists on the right to see" Mrs. Skripal, who is a Russian citizen.
A spokeswoman for the British Foreign Ministry said, "We are considering requests for consular access in accordance with our obligations under international and national law, including the rights and wishes of Julia Skripal."