British media report that Yulia Skripal, one of two Russians poisoned by nerve agent, has been released from the hospital.
BBC News said Tuesday the 33-year-old Skripal had been discharged from hospital and taken to a “secure” location on Monday.
Britain’s Press Association says hospital officials plan to make an official statement shortly.
The British government is likely to keep details about her location secret given the sensitivity of the case.
Yulia Skripal was in critical condition after the March 4 nerve agent attack, apparently aimed at her father, former Russian spy Sergei Skripal.
She has arrived on an Easter visit from Moscow the day before the attack.
He remains hospitalized but officials say he is improving rapidly.
Britain has accused the Russian government of masterminding the attack on the Skripals, who were found unconscious on a bench in the English city of Salisbury March 4.
Britain says they were poisoned by a military grade nerve agent that could only have been made in Russia.
Russia has denied the allegation, which has led to the expulsion of diplomats on both sides.
Britain has been backed by the United States and its European allies in blaming Russia for the assault.