Yulia Skripal, who was poisoned with a nerve agent in the English city of Salisbury last month along with her Russian ex-spy father, has been discharged from hospital, the BBC and Sky news reported Tuesday.
The BBC said the 33-year-old was released on Monday and taken to a secure location, while her father Sergei Skripal remains in hospital.
A spokesman for the state-run National Health Service (NHS) told AFP that a press conference had been scheduled for 08:30am (0730 GMT).
There was no comment from the Metropolitan Police, which has been leading the investigation into the March 4 poisoning.
In a statement last week, staff at Salisbury hospital said of Yulia Skripal: “Her strength is growing daily and she can look forward to the day when she is well enough to leave the hospital.”
Her father, a former Russian military official who sold secrets to Britain before moving there in a 2010 spy swap, was also said to be “improving rapidly”.
Britain and its allies have blamed Russia for carrying out the attack, the first offensive use of a nerve agent in Europe since World War II, sparking a major diplomatic crisis.